Compact, high-efficiency radar assembly

ABSTRACT

Provided is an array antenna divided into a plurality of sub-arrays disposed along a first dimension, wherein each sub-array comprises: a plurality of frequency scannable elements disposed along the first dimension and a plurality of phase shifters or transmit/receive (T/R) modules disposed along a second spatial dimension, each phase shifter or T/R module connected to a plurality of frequency scannable elements disposed along the first spatial dimension; and one or more processors being configured to generate a recurring radar waveform having a transmit portion, the transmit portion having multiple successive pulses at different frequencies to generate transmit beams by the array antenna at different angles in the first dimension; control at least one of the plurality of phase shifters or T/R modules along the second dimension to cause the transmit beams to be generated by the array antenna at different angles in the second dimension; and process return signals received by the plurality of sub-arrays to estimate a target location.

CROSS-REFERENCE TO RELATED APPLICATIONS

No cross-reference is present at this time.

BACKGROUND

The term “radar” is an acronym for “radio detection and ranging.” Radarsuse electromagnetic waves to detect objects, if present, within a givenvolume of space. Radars can be used to determine various characteristicsregarding an object's state, such as a location, speed, direction,range, altitude, elevation, and the like. A radar operates by emittingan electromagnetic (or “EM”) wave, such as a radio wave, directed at avolume in space and detecting portions of the radio wave that reflectoff an object located within the volume. In some cases, a radar scans aregion of space by focusing electromagnetic energy into an angular beam,which is then swept across the surveillance volume in search of targets.The direction from the radar to a target is typically described in termsof a pair of angles, such as azimuth and elevation.

SUMMARY

The following is a non-exhaustive listing of some aspects of the presenttechniques. These and other aspects are described in the followingdisclosure.

Some aspects relate to a radar assembly, which may include transmitterantenna sub-assemblies and receiver antenna sub-assemblies. Transmissionof signals from the transmitter antenna sub-assemblies may be controlledby transmitter signal processing circuitry. A direction for one or moretransmission signals, such as emitted from the transmitter antennasub-assemblies or from antenna elements of the transmitter antennasub-assemblies, may be controlled in a first spatial direction by afirst means. The direction for the one or more transmission signals maybe controlled in a second spatial direction by a second means, where thefirst spatial direction and the second spatial direction may beorthogonal. In some aspects, the first means or the second means may bea phase-shifted means of control, which may correspond to activebeam-steering (e.g., using integrated circuitry, such as phase shiftersor transmit/receive modules) or passive beam-steering (e.g., usingfrequency scanning). In some aspects the first means or the second meansmay be a directional means of control (e.g., mechanical beam-steering).

Signals received by the receiver antenna sub-assemblies may be processedby receiver signal processing circuitry. A preferentially sensitive(e.g., a “preferred”) direction for one or more received signals, suchas received by the receiver antenna sub-assemblies or from antennaelements of the receiver antenna sub-assemblies, may be controlled in afirst spatial direction by a first means. The preferred direction forthe one or more received signals may be controlled in a second spatialdirection by a second means, where the first spatial direction and thesecond spatial direction may be orthogonal. The direction of thereceived signal may correspond to a direction from which the receivedsignal is reflected from a target in the surveillance volume. In someaspects, the first means or the second means may be a phase-shiftedmeans of control, which may correspond to active beam-steering (e.g.,using integrated circuitry, such as phase shifters or transmit/receivemodules) or passive beam-steering (e.g., using frequency scanning). Insome aspects the first means or the second means may be a directionalmeans of control (e.g., mechanical beam-steering).

Some aspects relate to a radar assembly, which may include a transmitantenna assembly. The transmit antenna assembly may include an activebeam-steering circuit and a passive beam-steering circuit. The activebeam-steering circuit may be configured to control, along a firstspatial dimension, a direction of an electromagnetic beam that scans avolume of the external environment to determine whether objects arelocated within the volume. The passive beam-steering circuit may beconfigured to control, along a second spatial dimension, the directionof the electromagnetic beam that scans the volume. The passivebeam-steering circuit may include a set of antenna elements and a set offrequency scanned array cards respectively associated with the first setof antenna elements. The antenna elements may be configured to transmitthe electromagnetic beam. Each frequency scanned array card may beconfigured to cause an input signal to be phase-shifted by a respectiveamount such that, along the second spatial dimension, theelectromagnetic beam transmitted via the set of antenna elements isoutput in a direction of the volume. The phase-shifted input signal maybe used by a respective antenna element to output a respective componentof the electromagnetic beam, and the electromagnetic beam may be formedbased on a combination of the respective components.

Some aspects include the radar assembly further including a receiveantenna assembly. The receive antenna assembly may include an activebeam-steering circuit and a passive beam-steering circuit. The passivebeam-steering circuit of the receive antenna assembly may include a setof antenna elements, which may be the same or different from the set ofantenna elements of the transmit antenna assembly and may also include aset of frequency scanned array cards respectively associated with theset of antenna elements of the receive antenna assembly. The set ofantenna elements of the receive antenna assembly may be configured toreceive a reflected electromagnetic signal resulting from theelectromagnetic signal output by the transmit antenna assemblyreflecting off one or more candidate objects located within thesurveillance volume. The set of frequency scanned array cards of thereceive antenna assembly may each be configured to receive a reflectedelectromagnetic beam of a given frequency from a corresponding directionalong the second spatial dimension via constructive interference. Theactive beam-steering circuit of the receive antenna assembly may beconfigured to control, along the first spatial dimension, a preferreddirection that the set of antenna elements of the receive antennaassembly will receive energy to detect reflections from the transmittedelectromagnetic beam.

Some aspects of the radar assembly further include the first activebeam-steering circuit being thermally coupled to a first heatsink, suchthat heat from the first active beam-steering circuit is conducted to anexternal environment, and the second active beam-steering circuit beingthermally coupled to the first heatsink, such that heat produced by thesecond active beam-steering circuit is thermally dissipated to theexternal environment via the first heatsink.

Some aspects include an antenna assembly, which may include an activebeam-steering circuit and a passive beam-steering circuit, where thepassive beam-steering circuit may include a set of antenna elements anda set of frequency scanned array cards. The active beam-steering circuitmay be configured to control, along a first spatial dimension, adirection of an electromagnetic beam that scans a volume of an externalenvironment to determine whether objects are located within the volume,wherein the active beam-steering circuit is thermally coupled to aheatsink such that heat from the active beam-steering circuit isconducted to the external environment. The passive beam-steering circuitmay be configured to control, along a second spatial dimension, thedirection of the electromagnetic beam. The set of antenna elements maybe configured to transmit the electromagnetic beam and receive areflected electromagnetic beam resulting from the electromagnetic beamreflecting off an object. The set of frequency scanned array cards maybe respectively associated with the set of antenna elements, and eachfrequency scanned array card of the set of frequency scanned array cardsmay be configured to cause an input signal to be phase-shifted by arespective amount such that, along the second spatial dimension, theelectromagnetic beam transmitted via the set of antenna elements isoutput in a direction of the volume. The phase-shifted input signal maybe used by a respective antenna element of the set of antenna elementsto output a respective component of the electromagnetic beam, and theelectromagnetic beam may be formed based on a combination of therespective components.

Some aspects include a process for operating the above-mentioned radarassembly as well as a process for fabricating the above-mentioned radarassembly, transmit antenna assembly, or receive antenna assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects and other aspects of the present techniqueswill be better understood when the present application is read in viewof the following figures in which like numbers indicate similar oridentical elements:

FIG. 1 is a system diagram that illustrates an example radar assembly,in accordance with one or more embodiments;

FIG. 2 is a system diagram that illustrates another example radarassembly, in accordance with one or more embodiments;

FIG. 3A illustrates an example transmit antenna assembly, in accordancewith one or more embodiments;

FIG. 3B illustrates a frequency scanned array card, in accordance withone or more embodiments;

FIG. 3C illustrates an example array of antenna elements, in accordancewith one or more embodiments;

FIG. 3D illustrates an example electromagnetic beam generated by a setof antenna elements, in accordance with one or more embodiments;

FIG. 3E illustrates an example receive antenna assembly, in accordancewith one or more embodiments;

FIG. 3F illustrates an example transmit/receive antenna assembly, inaccordance with one or more embodiments;

FIG. 4 illustrates an example use case of the radar assembly, inaccordance with one or more embodiments;

FIG. 5 illustrates an example architecture for an array of antenna T/Rsub-arrays, in accordance with one or more embodiments;

FIG. 6 illustrates an example T/R sub-array comprising antenna elements,in accordance with one or more embodiments;

FIG. 7 illustrates an example architecture for an array of receiverantenna sub-arrays and transmitter antenna sub-arrays, in accordancewith one or more embodiments;

FIG. 8 illustrates an example transmitter sub-array comprising antennaelements, in accordance with one or more embodiments;

FIG. 9 illustrates an example receiver sub-array comprising antennaelements, in accordance with one or more embodiments; and

FIG. 10 illustrates an example computing system with which one or moreembodiments may be implemented.

While the present techniques are susceptible to various modificationsand alternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Thedrawings may not be to scale. It should be understood, however, that thedrawings and detailed description thereto are not intended to limit thepresent techniques to the particular form disclosed, but to thecontrary, the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the presenttechniques as defined by the appended claims.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

To mitigate the problems described herein, the inventors had to bothinvent solutions and, in some cases just as importantly, recognizeproblems overlooked (or not yet foreseen) by others in the field ofradar. Indeed, the inventors wish to emphasize the difficulty ofrecognizing those problems that are nascent and will become much moreapparent in the future should trends in industry continue as theinventors expect. Further, because multiple problems are addressed, itshould be understood that some embodiments are problem-specific, and notall embodiments address every problem with traditional systems describedherein or provide every benefit described herein. That said,improvements that solve various permutations of these problems aredescribed below.

If the transmit beam of the transmit antenna assembly is smaller thanthe angular extent of the desired surveillance volume, the beam may bescanned/steered across the surveillance volume—either mechanically orelectrically. An electrically scanned array (ESA) antenna may direct EMenergy in a desired direction by transmitting a reference signal whichmay be phase shifted for some or each antenna element. The phaseshifting may be designed so that the per-element signals interfereconstructively in a desired direction and interfere destructively inother directions. The per-element phase shifts may be produced in manyways. In an active ESA, each antenna element may have its own transmitintegrated circuit (IC), which may include both power amplification andphase shifting circuitry. In a passive ESA, a single transmitter may beconnected to substantially all elements and each element may have itsown phase shifter (which may be a phase shifting IC). In a meta-materialESA, the EM properties of the transmission line and/or radiatingelements may be altered to impart a desired phase shift in theper-element transmitted signals. In a frequency-scanned ESA, thefrequency of the transmit signal may also or instead be altered, wheresuch alteration may impart a desired per-element phase shift inconjunction with an appropriately designed serpentine transmission lineconnecting the radiating elements to the transmitter. These approachesmay provide various transmitter performance or cost benefits. Tooptimize performance while minimizing cost, it may be beneficial for amethod to be used to scan the transmitter beam in the azimuth directionand for a different method to be used to scan the beam in the elevationdirection.

The set of antenna elements of the receive antenna assembly may beconfigured to receive a reflected electromagnetic signal resulting fromthe electromagnetic signal output by the transmit antenna assemblyreflecting off one or more candidate objects located within thesurveillance volume. If the extent of the receive antenna assembly'sangular sensitivity is smaller than the desired surveillance volume, thedirection of the receiver's “beam” (e.g., main lobe or peak sensitivity)may be scanned, steered, or otherwise directed across one or moredirections, either mechanically or electrically. Methods enumerated forelectrically scanning transmit arrays may similarly be applied toreceive arrays, such as active scanning (e.g., using a low-noiseamplifier per antenna element), passive scanning, meta-materialscanning, and frequency scanning. Here again, techniques for receiveESAs may provide various receiver performance or cost benefits, andhybrid approaches that use different methods in the azimuth andelevation directions may be beneficial.

In addition to the scanning method selected for the transmit and receiveantenna arrays, there are other radar design decisions that may haveimpacts on the performance and cost. For example, a radar may have asingle antenna array that is used for both transmit and receiveoperations, or it may have separate transmit and receive arrays. Use ofa single antenna array may reduce the amount of IC circuitry needed toimplement the radar, but it may also correspond to a more complicatedprinted circuit board layout, a higher heat density for the array duringoperation, or a forfeiture of the ability to simultaneously transmit andreceive. In another example, a radar may be actively cooled (e.g., usingfans or other coolants driven by pumps) or passively cooled (e.g., viaconvection, dissipation, etc. through fluid or gas heat transfer). Theuse of active cooling may permit higher heat density (e.g.,corresponding to higher power operation or denser IC layout) in thearray or accompanying circuitry than may be acceptable in uncooled orpassively cooled radars. However, active cooling may correspond to lowerreliability because the radar may fail if the active cooling sourcefails. In yet another example, modern radars may be implemented usingconcepts from software-defined radios, wherein components that wereoriginally implemented in analog circuitry are now implemented insoftware on a digital computer or embedded processor, such as acentralized processor unit (CPU), graphical processor unit (GPU),application-specific integrated circuit (ASIC), or field-programmablegate array (FPGA). The use of digital processing within a radar mayrequire the presence of both analog-to-digital (A/D) converters anddigital-to-analog (D/A) converters, to convert signals between analogand digital domains and vice versa. Herein “A/D converters” is used in anon-limiting sense to refer to A/D converters and to D/A converters orany other converters between digital and analog domains in anydirection. Inclusion of A/D converters (or inclusion of additional A/Dconverters) may increase the opportunity to use advanced signalprocessing (such as digital beamforming) to improve radar performance,but it may also increase cost and heat generation due to the inclusionof additional digital processors.

A novel radar architecture may maximize target detection and trackingperformance while maintaining reasonable cost by jointly optimizing theselection of transmit/receive scanning, radar cooling, and digitalprocessing architecture. Radar detection performance is largely drivenby a radar's effective radiated power and its receiver sensitivity.However, higher radiated power requires higher cooling capacity. Radartracking performance is driven by range accuracy and angular accuracy,where the former is largely driven by signal-to-noise ratio (SNR) andsignal bandwidth, while the latter is largely driven by SNR and the sizeof the antenna array in wavelengths (spatial bandwidth). For physicallycompact radars, it may be desirable to use higher frequency radarsignals to increase the electrical size (e.g., in wavelengths) of theantenna array (which may be accomplished without increasing its physicalsize), thereby improving angular accuracy. However, as frequencyincreases, the spatial constraints of planar phased array architecturesbecome a significant challenge, as does the increased heat density.Generally, as transmission frequency increases, spacing between elementsof the phased array decreases, but thermal dissipation required by theelectronics does not generally significantly decrease with frequency.

Angular accuracy may also be improved by implementing a sub-arrayarchitecture where the antenna array is sub-divided into mutuallyexclusive collections of antenna elements, where each sub-array has itsown A/D converter, so multiple return signals can be measuredsimultaneously. For example, an antenna array may be sub-divided intoquadrants: left-up, left-down, right-up, and right-down. The antennaarray may also be sub-divided into greater than four sub-units,including unequal numbers of sub-units along a first direction and asecond direct—for example 8 units, 16 units, 36 units, etc. Angularaccuracy in azimuth that is significantly less than the azimuth angularextent of the antenna beam (e.g., accuracy smaller than antenna beamdimension) may then be achieved by applying interferometric (e.g.,monopulse) techniques to the two or more signals, such as, for example,a signal generated by summing the left-up and left-down receiverchannels and a signal generated by summing the right-up and right-downreceiver channels. In a similar fashion, angular accuracy in elevationthat is much less than the elevation angular extent of the antenna beammay also be achieved by applying interferometric (e.g., monopulse)techniques to the two or more signals, such as, for example, a signalgenerated by summing the left-up and right-up receiver channels and asignal generated by summing the right-down and left-down receiverchannels. Alternatively, maximum likelihood estimation techniques may beapplied to all receiver channels (e.g., four receiver channels: left-up,left-down, right-up, and right-down for an antenna array divided intoquadrants) jointly to achieve angular accuracy in both azimuth andelevation that is less than the angular extent of the antenna beam inthese dimensions. However, this improved angular accuracy may increasethe cost and heat generation of the radar by requiring additional A/Dconverters (e.g., one per sub-array).

Radar costs are largely driven by the cost of the transmit/receiveintegrated circuitry and the costs of integration hardware (cables,connectors, etc.). Certain radar architectures, like planararchitectures, lend themselves to reduced complexity and thus reducedcost by addressing the integration cost component. Phased arrays canalso reduce cost by reducing the number of moving mechanical components.It should be emphasized that embodiments are not limited to systems thatavoid all of these issues and discussion of such issues should not beread as a disclaimer or disavowal of claim scope.

Some embodiments mitigate the spatial challenges that arise as frequencyincreases, the thermal challenges that arise with increased elementdensity, or the cost challenges that arise as the number of phased arrayelements increases. The antenna architecture may include a heatsink, anactive electronic scanning board, passive scanning boards and antennaelements, and a radome. The radar architecture may include a transmitantenna, a receive antenna, a radio frequency (RF) isolator separatingthe two antennas, and associated radar processing hardware.

Some embodiments are expected to mitigate some or all of theabove-mentioned problems by separating the transmit and receiveantennas, which reduces the complexity of the electronics, and allowssimultaneous transmit and receive, which reduces the required peak powerneeded to be radiated for a given radar detection requirement. Someembodiments mitigate the problem of transmit-receive interferencethrough the use of an RF (radio frequency) isolator to reduce the RFsignal energy transferred from the transmit antenna to the receiveantenna. Some embodiments are also expected to mitigate some or all ofthe above-mentioned problems by separating the electronic scanning intoan active scanning component and a passive scanning component (which maybe referred to as a hybrid scanning architecture) which is expectedto: 1) allow the heat-generating electronics for the active scanningcomponent to be implemented in a planar architecture on a single printedcircuit board (PCB) mated directly to a heat sink for efficient andpassive thermal handling; 2) allow antenna elements that are passivelyscanned to be arranged on planar PCBs that have no powered integratedcircuitry, and therefore are inexpensive to manufacture and do notrequire connection to a heat sink; 3) allow the electronics to achievethe phased array antenna element spacing corresponding to the Ku-band bysignificantly reducing integrated circuitry from one of the twodimensions of beam scanning (e.g., such that the integrated circuitryneeded for the antenna arrays scales according to the number of columns(or another dimension) in the arrays, rather than the total number ofantenna elements (or components in both a first and a seconddimension)); or 4) significantly reduce the overall number of activeelectronic components, thereby reducing cost and heat generation.

For certain use cases, it is desirable for radar systems to be able todetect objects in the Ku frequency band (12-18 GHz). As the frequenciesincrease, the size of the components used to form the radar, such as theantenna elements used to output EM waves and detect reflected EM waves,decreases. As the radar components decrease in size, the costs tofabricate the radar systems increase. In addition, these radar systemscan produce substantial amount of thermal output which manifests as heatdensity, particularly at such high frequencies. Active coolingtechniques, such as liquid nitrogen, are not feasible when the radar isused in the field, as it is costly and difficult (and dangerous) totransport. These and other drawbacks exist, though it should beemphasized that embodiments are not limited to systems that avoid all ofthese drawbacks and discussion of such issues should not be read as adisclaimer or disavowal of claim scope.

As the use of radars continues to increase, the needs of radar systemsand radar system users also expand, shift, and adapt. One use of radarthat has important security and safety implications is the use of radarfor short-range air surveillance applications. Some examples ofshort-range air surveillance applications include, but are not limitedto—which is not to imply that other lists are limiting-air defenseapplications, beyond line-of-sight unmanned aircraft operations ordefense, ground-based sense and avoid, or other air-space managementapplications, or combinations therefore. In some cases, air-spacemanagement applications may include applications at smaller airportswhere a larger radar is not available or not affordable.

Some of the challenges faced by manufacturers when developing radars forshort-range air surveillance applications include providing electronicbeam-steering in two dimensions at Ku-band (12-18 GHz) frequencies andnear Ku-band (8-22 GHz) frequencies. It should be noted that otherportions of the electromagnetic spectrum, occupying different frequencyranges may also be used instead of, or in addition to, the frequenciesof the Ku-band, which is not to suggest that other described featuresare limiting. In some use cases, the challenges faced by manufacturersto build radars that provide electronic beam-steering in two-dimensionsat Ku-band frequencies may be similar or share similarities with thechallenges experienced developing such a radar operating at otherfrequency bands. For example, electronic beam-steering may be neededbetween 10-20 GHz, 1-20 GHz, or other frequency ranges. The frequencyrange may be adjusted based on a geographic location of the radar. Forexample, North American locations may include regions represented by the11.7-12.2 GHz range for fixed satellite service.

As the frequency band that the radar operates at increases, the size andspacing of the components used to fabricate the radar generallydecrease, following the inverse relationship of wavelength andfrequency. For example, the spacing between antenna elements in a phasedarray antenna, examples of which are described below, may be one half ofthe transmitted or received wavelength, including spacing of half of thetransmitted or received wavelength plus or minus 5% or 20%, (as measuredfrom edge to adjacent edge) in order to mitigate loss of performancethrough grating lobes, e.g., about one cm apart for Ku-band use cases.For example, antenna elements used to form portions of an antennaassembly for a radar are designed based on the wavelength of the signalbeing transmitted/received. In the Ku-band, where the frequencies of theelectromagnetic signals are between 12-18 GHz, the wavelength will bebetween 1.67-2.5 cm. As another example, for infrared signals, having afrequency between 300 GHz and 430 THz, the wavelength is between 700 nmand 1 mm. Along with the size decreases of the components, thetolerances with which those components are made (or operated) may alsodecrease, meaning higher levels of precision are needed duringfabrication, and thermal budgets can become tighter as moreheat-generating components need to be packed into a smaller volume.Generally, the more precise and compact a structure is, the greater thetime and cost it takes to produce.

In some embodiments, an antenna assembly includes an antenna and variousother components, e.g., beam-steering circuits. An antenna (like aphased array antenna) may be formed of one or more antenna elements. Insome embodiments, an antenna element is a portion (like a conductivemember) of a phased array antenna involved in the reception ortransmission of a signal, e.g., the electromagnetic radiation output asa beam towards a volume in space. The size and shape of the antennaelements may be determined based on the frequency band (or bands) withwhich the radar is to operate. The shape and size will be related to thewavelength of the electromagnetic radiation to be output and received.Antenna elements may be distinct conductors electrically connected(e.g., independently of one another, or with some different set ofcircuit elements) to transmitters or receivers.

Another challenge addressed in some embodiments is cooling. To steer theelectromagnetic beam, whether during transmission or reception, “active”components are used. An active component may dynamically switch whichantenna elements receive energy to steer an electromagnetic beam. Someembodiments include components actuating or otherwise causing acomponent to be physically moved. For example, the transmit/receiveantenna elements, cables, connectors, motors, etc. Active and passivecomponents may generate heat when conducting electrical signals.Electrical components generally produce heat, and as radar componentscarry electrical signals heat is generated by conduction, switching,power transfer, and other electrical operations. As the internaltemperature of the radar increases, the performance of the radar canbecome impaired in some use cases. This technical problem can beexacerbated when the external environment, such as the environmentwherein which the radar is deployed and used, is itself hot. Forexample, desert environments, where the temperature can exceed 30degrees Celsius, can increase a base temperature of the radar such thatthe additional heat produced by the active components of the radar causethe radar to overheat and subsequently malfunction.

One approach to thermal management is to include some form of “activecooling” with the radar. Active cooling components generally consumeenergy in service of removing waste heat, but such approaches can beundesirable in some cases (which is not to suggest that they, or anyother approach for which tradeoffs are discussed, are disclaimed). Forexample, active cooling via evaporative cooling with liquid nitrogen orliquid helium is often infeasible in certain use cases, such longer-termuse, operation in remote desert environments, operation innon-terrestrial environments, etc. Refrigeration systems similarly canimpose cost, size, noise (e.g., vibration), and complexity tradeoffs andcan have compressors or fans break. (Peltier elements, e.g., disposedbetween a heat sink and a heat-generating component with the hot-sideadjacent the heat sink, consume energy in service of removing wasteheat, but avoid other forms of active movement and are treated as a formof passive cooling herein.)

Mechanical complexity, generally, is desirable to avoid for some usecases. Some antenna architectures lend themselves to reduced complexity,which is expected to reduce the cost of fabricating the radar. Anexample antenna architecture that can be used to reduce complexity is aplanar architecture. In some embodiments, a planar architecture includesantenna elements arranged in an array on a surface, e.g., as a one- ortwo-dimensional array on a planar surface which is not to disclaim athree-dimensional or quasi-three dimensional array in which the surfaceis not planar, is not perfectly planar (for example, has features orfeatures which overlap in a third dimension which are much smaller thanfeatures in the directions of the planar surface), is curved, etc. Forinstance, a planar array may include antenna elements arranged (such asin a rectangular or hexagonal grid) in a N×M grid, where N and M may beequal in some embodiments. In other examples, the array may be on asurface that is not co-planar, e.g., with the array conformally disposedon a sphere or section of a sphere. In some embodiments, N and M areintegers, and can have a value of 2 or more, 4 or more, 8 or more, 16 ormore, 32 or more, 64 or more, 128 or more, or other values.

As frequency increases, the spatial constraints of the planar arraydrive thermal constraints that become challenging, particularly due tothe increased heat density, as mentioned above. In particular, at higherfrequency ranges, such as for radars that are to operate in the nearKu-band, the spacing between elements of the antenna array may berelatively small, like on the order of 0.5 to 2 cm between antennaelements, which causes the density of heat generating electronics to berelatively large.

An antenna having a phased array architecture, which is referred toherein interchangeably as a “phased array antenna,” may include an arrayof antenna elements that are used for transmitting or receivingelectromagnetic signals, which together form a directional radiationpattern for transmission and a directionally favored gain for reception.Examples include both phase scanning and frequency scanning antenna.Patterns in constructive and destructive interference from signals sentor received by each of the antenna elements and combined may impart thatdirectionality. A directional radiation may cause an overall beam ofelectromagnetic radiation steered in a particular direction. Phasedarray antennas have certain benefits over other types of antennaassemblies. For instance, a phased array antenna may allow for rapidbeam-steering, multiple phase centers, low sidelobes, etc.

The electromagnetic radiation output by the antenna may be described inphysical space using a vector. The magnitude of the vector can becontrolled by adjusting the gain of the electromagnetic radiation. Thelocation in space where the electromagnetic radiation is directed can bedescribed using an azimuthal angle and an angle of elevation.

A transmit antenna assembly may include a plurality of antenna elements.Each antenna element may output a portion of a resulting electromagneticbeam. The total electromagnetic beam is formed by combining the portionoutput by each antenna element through constructive and destructiveinterference. In some embodiments, beam direction is modulated withoutthe radar assembly moving by applying a phase shift to some or all ofthe antenna elements' signals so as to adjust the direction of theresulting electromagnetic beam. In some embodiments, the radar may alsomove. In some embodiments, one or more phase shifters may be included inthe transmit antenna assembly (or the radar assembly including thetransmit antenna assembly). For example, each antenna element may have acorresponding phase shifter that applies a respective phase shift to theinput signal fed to or from the antenna element. However, fewer phaseshifters may be included, such as less than one phase shifter perantenna element. In some embodiments, the transmit antenna assembly mayinclude a source element (like a transmitter) used to generate a sourcesignal. The source element may provide the source signal to each phaseshifter to apply the phase shift to a respective component of the sourcesignal. After the source signal is provided, each element signal (thecomponent of the source signal provided to each phase shifter) may bephase shifted by the designated amount of phase-shifting using therespective phase shifter. The phase-shifted element signal may beprovided to the corresponding antenna element (or an amplifier toamplify the signal, then to the antenna element) to be output. In somecases, phase shifts may monotonically increase in a first directionalong a spatial dimension of an array of antenna elements when scanningto one side and monotonically decrease in the opposite direction alongthe spatial dimension of the array of antenna elements when scanning tothe opposite side. The amount of increase or decrease in phase shiftbetween antenna elements may be modulated, for example to adjust thedirectionality.

A receive antenna assembly may include similar components as that of thetransmit antenna assembly. A receive antenna assembly may furtherinclude low-noise amplifiers coupled to the antenna elements and a powercombiner may be used to combine the received signals (which may becombined after being phase shifted back by the same or different phaseshifters coupled to the antenna elements). The combined received signalmay be provided to a receiver element, which may convert the combinedreceive signal into the digital domain and provide the resulting data toanother component to analyze whether any objects are present within avolume defined by the directionality of the output electromagnetic beam.

In some embodiments, a single antenna assembly may be used for bothtransmit and receive operations, e.g., at different times, alternatingbetween roles. In some such cases, the antenna assembly may include oneor more transmit/receive (T/R) modules. The T/R module may allow theantenna assembly to simultaneously, e.g., within 1 second of each other,within 1 millisecond of each, within 1 nanosecond of each other, and thelike, transmit electromagnetic radiation towards a volume in space andreceive a portion of the electromagnetic radiation that reflects offobjects located within the volume.

In some embodiments, the interface pattern produced by a two-dimensionalplanar phased array can be represented by Equation 1:

$\begin{matrix}{{{A{F\left( {\theta,\varnothing} \right)}} = {4{\sum\limits_{m = 1}^{M/2}{\sum\limits_{n = 1}^{N/2}{w_{mn}{\cos\left\lbrack {\left( {{2m} - 1} \right)u} \right\rbrack}{\cos\left\lbrack {\left( {{2n} - 1} \right)v} \right\rbrack}}}}}},{{{where}u} = {\frac{\pi d_{x}}{\lambda}\left( {{\sin\theta\cos\phi} - {\sin\theta_{0}\cos\phi_{0}}} \right)}},{{and}{{v = {\frac{\pi d_{y}}{\lambda}\left( {{\sin\theta\sin\phi} - {\sin\theta_{0}\sin\phi_{0}}} \right)}}.}}} & {{Equation}1}\end{matrix}$

In Equation 1, w_(mn) represents the amplitude of the weight of a givenantenna element at its particular position in the array, d_(x) and d_(y)represent the spacing between the antenna elements, θ represents theangle of elevation that the electromagnetic radiation is to be steered,θ represents the azimuth angle, and A represents the wavelength of theoutput signal. The two-dimensional planar array may function by creatingelectromagnetic waves directed in a particular direction, wheresuperposition of the electromagnetic waves produced by each antennaelement generate the output electromagnetic beam directed towards atarget location in space.

In some embodiments, antennas implementing a phased shifted planar arraymay be used to detect whether a given volume in space includes anyobjects, or the radar can be configured to scan across a range ofvolumes to determine whether any objects are present within ageneralized field of view of the radar. Some embodiments adjust one ormore active phase shifters to apply different phase shifts to therespective source signal; some embodiments adjust the frequency of thesource signal; or some embodiments do both. A phased array antenna thataccomplishes beam-steering by adjusting the frequency of source signalprovided to the antenna elements is referred to as a frequency scanningarray. As an example, an antenna assembly may include antenna elements,directional couplers connected respectively to antenna elements, andmatched filters respectively connected to directional couplers. Eachantenna element may be spaced apart by a distance d, which is thedistance between the centers of adjacent elements (although other pointsof reference may be used to measure spacing), and which may be selectedbased on the frequency band the antenna assembly is designed to operate,e.g., at approximately one half the wavelength of the electromagneticsignals. In some embodiments, the directional couplers may be configuredto control the signal to be transmitted or received by the respectiveantenna elements. The matched filters may facilitate balancing the loadsbetween the connections of the directional couplers and the matchedfilters to minimize (or at least reduce) an amount of reflection of thesignal within the transmission lines. The matched filters may be coupledto a transmitter/receiver to process the signals.

In some cases, a linear array (as opposed to a two-dimensional array)may be used to cause an output electromagnetic beam to be adjusted toscan across a field of view. For example, an angle of the vectordescribing the electromagnetic beam can range between values Ø=0 andØ=71 (180 degrees) where these are non-limiting values. For example, theangle of the vector can be described as varying between Ø=−π/2 andØ=π/2. The frequency scanning technique may allow the electromagneticbeam to scan across some or all values of Ø by adjusting the frequencyof the source signal provided to the antenna elements. Frequencyscanning is a desirable technique for performing beam-steering becauseno moving parts (e.g., parts causing physical movement, motors, etc.)are needed, reducing the chances of malfunction, as well as notrequiring any cooling (active or passive). Another advantage of thefrequency scanning technique is that it does not require phase shifters.Removal of phase shifters from the antenna assembly can reduce the costof fabrication, as well as decrease the complexity of the build.

In some embodiments, the radar assembly may include frequency scanningarray components that operate to cause each antenna element to output aportion of the electromagnetic beam, with frequency changing over anamount of time so as to execute a scan of physical space. For example,in one dimension, the frequency scanning array components may functionto move the electromagnetic beam from [−θ, +θ] or [−ϕ, +ϕ], where θrepresents the angle of elevation and can range between 0 and90-degrees, and θ represents the azimuth angle and can range between 0and 180-degrees, though the example ranges are not to be construed aslimiting. In some embodiments, the antenna elements may be fed seriallywith a source signal that has a same frequency, such that each antennaelement receives a component of the source signal that may have adifferent phase (e.g., when received at the antenna element) at a giventime. For example, the frequency scanning array components may include along trace that is arranged in a manner so as to provide a particularamount of delay, for example where the amount of delay is due to thelength of the trace, which affects the phase of the signal. A long traceor traces of different lengths can affect the phase or phase coherenceof multiple signals by generating a phase offset as a function of thespeed of transmission of the signal along the trace (e.g., the signal isdelayed by a time equal to the distance of the trace divided by thespeed of transmission along the trace). If the length and arrangement ofthe traces on each frequency scanning array component is substantiallythe same, each antenna element may then output a portion of theresulting electromagnetic beam that is substantially in phase with theother portions. However, if the frequency is changed (which changes thenumber of wavelengths which correspond to the length of the trace), thespecifically designed trace may no longer cause the portions of theelectromagnetic beam output by each antenna element to be substantiallyin phase, and a phase shift between the portions of the electromagneticbeam may occur. For example, two traces which are of length X and Y maybe in phase for a first frequency F1 with a wavelength λ1, where X=n*λ1and Y=m*λ1 where n and m are integers. In the same example, the twotraces may not be in phase for second frequency F2 with a wavelength λ2,where X=p*λ2 and Y=q*λ2, where at least one of p and q is not aninteger. In some cases, the frequency of the source signal may beadjusted, while the arrangement and length of the trace of eachfrequency scanned array element may also be adjusted. The resulting beammay therefore be directed in a particular direction based on thesuperposition of the portions of the electromagnetic beam.

Some embodiments include radars, and antenna assemblies for radars,which are configured to provide beam-steering in two dimensions, such asazimuth and elevation, and operate in the Ku frequency band, e.g., 12-18GHz. Some embodiments include using passive beam-steering techniques,such with frequency scanned array cards, to scan regions of space in one(or more) spatial dimensions, such as elevation. For example, thefrequency associated with the frequency scanned array cards may be usedto determine an elevation of an output electromagnetic beam, anelevation of an object detected by the output of the electromagneticbeam (such as based on correspondence of frequency, etc.). In somecases, the frequency scanned array cards may be used additionally, oralternatively, to scan regions of space in an azimuthal dimension. Someembodiments include a radar assembly that is expected to mitigate (or insome cases overcome) the aforementioned problems while also reducingproduction costs and increasing scalability. Some embodiments include aradar assembly and an antenna assembly thereof that are passivelycooled. Passive cooling is expected to further reduce costs or size byeliminating or reducing the need for active cooling. Some embodimentsperform concurrent transmit/receive operations.

In some embodiments, a radar assembly may include a transmit antennaassembly and a receive antenna assembly. FIG. 1 depicts an example radarassembly 100, which may include transmit antenna assembly 102, receiveantenna assembly 104, isolation component 106, a frequency conversioncomponent 108, a power distribution component 110, a computing system112, or other components. FIG. 2 shows radar assembly 200, which may besubstantially similar to radar assembly 100 of FIG. 1, with theexception that radar assembly 200 includes a single antenna assembly202, and a transmit/receive (T/R) module 220. While only one T/R module220 is depicted for reasons of simplicity, multiple T/R modules whichmay allow transmit and receive mode operation on a single antennaassembly 202 (or on one or more antenna element) may be present. T/Rmodule 220 may comprise T/R module or unit for antenna assembly 202,multiple T/R modules for antenna assembly 202, one transmit/receive(T/R) module per antenna element of antenna assembly 202, etc. Antennaassembly 202 may be configured, such as by using T/R module 220, toperform both transmit and receive operations. In some embodiments, thetransmit and receive operations may be performed in parallel, e.g.,within 1 second of one another, within 1 millisecond of one another,within 1 nanosecond of one another, etc.

In some embodiments, radar assembly 100 (or 200) may be portable (e.g.,movable from location to location), including mobile (e.g., operableduring transport). In some embodiments, radar assembly 100 (or 200) maybe 16″ by 22″ by 6.5″ in size. These dimensions should not be taken aslimiting, and in some embodiments radar assembly 100 (or 200) may belarger or smaller, such as half the size of the above dimensions or onthe order of 8″ by 11″ by 3″.

In some embodiments, transmit antenna assembly 102 may be configured toperform transmit operations where an electromagnetic beam is output fromone or more antenna elements of transmit antenna assembly 102. Theelectromagnetic beam may be steered by transmit antenna assembly 102such that it scans a particular region of space. Transmit antennaassembly 102 may be configured to determine whether objects are locatedwithin the scanned space and, if present, in some embodiments,responsive to control signals, track the objects' movements. To detectobjects, in some embodiments, transmit antenna assembly 102 outputs,using the antenna elements, electromagnetic radiation beams of aparticular width and shape such that the electromagnetic radiationtravels from the antenna elements out towards a given volume of space.The given volume may be defined using a coordinate system. For example,the volume's location may be specified in cartesian coordinates (x, y,z) relative to the location of the antenna elements. As another example,the location may be specified based on a gain needed for theelectromagnetic radiation to reach (with high probability) the location,a first angle defining an azimuth, and a second angle defining anelevation. More generally, the location analyzed by the electromagneticbeam defines a volume V, and that volume V can be moved about space tocarve out a region to be (or that has been) analyzed. If an object islocated within the volume V, then the electromagnetic beam may reflectoff the object and be directed back toward the radar assembly. Byanalyzing the reflected electromagnetic beam over time and space, motionof the object, as well as other characteristics, e.g., location, size,shape, number of objects, etc., can be determined, in some embodiments.In some embodiments, by analyzing the relationship between multiplereflected beams, such as by interferometry, motion or location of theobject, as well as other characteristics, e.g., size, shape, number ofobjects, etc., can be determined. The multiple reflected beams cancorrespond to multiple reflections of the same transmitted beam,reflections of multiple transmitted beams, or a combination thereof. Themultiple reflected beams may also be detected at one or more elements ofa receiver antenna. Interferometry may be used to measure theconstructive or destructive interference of a received signal and togain information about the path length of relative signals, and maytherefore be used to gain additional information about an objectcorresponding to multiple reflected signals, such as location, speed(for instance in red-shift or blue-shift), etc. Interferometry may beused in addition to or instead of some electronic signal processingmethods to derive such characteristics of detected objects.

As an example, FIG. 3A depicts transmit antenna assembly 102, which mayinclude a heatsink 302, an active beam-steering circuit 304, a set ofpassive beam-steering circuits 320 a-320 n (which may be referred tocollectively as passive beam-steering circuits 320 and individually aspassive beam-steering circuit 320), a radome 310, or other components.Each passive beam-steering circuit 320 may include a frequency scannedarray card 306 and an array of antenna elements 308, which may be anarray containing one element (e.g., a zero-dimensional array or pointarray), a linear array (e.g., a one-dimensional array), atwo-dimensional array, etc. For example, passive beam-steering circuit320 a may include frequency scanned array card 306 a and an array ofantenna elements 308 a (for simplicity one representative antennaelement 308 a is depicted in FIG. 3A which is not to disclaim thatmultiple antenna elements 308 a may be present), passive beam-steeringcircuit 320 b may include frequency scanned array card 306 b and anarray of antenna elements 308 b, and passive beam-steering circuit 320 nmay include frequency scanned array card 306 n and an array of antennaelements 308 n. In the foregoing, for simplicity, and unless otherwisespecified, the labels of “a”-“n” will be omitted when referringgenerally to the class of components at issue, e.g., array of antennaelements 308. The number “n” of passive beam-steering circuits 320 thatare included within the set of passive beam-steering circuits oftransmit antenna assembly 102 may vary depending on the performancecriteria of the radar assembly. For example, “n” may be 1 or more, 5 ormore, 10 or more, 50 or more, 100 or more, or other values. The greaterthe number “n” is, the greater the quantity of frequency scanned arraycards 306 and antenna elements 308 that may be included to producetransmit antenna assembly 102. Furthermore, and as noted in more detailbelow, the number of passive beam-steering circuits, and componentsthereof, included within transmit antenna assembly 102 may be the sameor different from the number of similar components included withinreceive antenna assembly 104.

As described herein, a frequency scanned array card may be referred tointerchangeably as a frequency scanned array component. Furthermore, theword “card” is not to be construed as requiring the frequency scannedarray card to have any particular form factor, e.g., to be of a same orsimilar size, shape, dimensionality, or style as a playing card,notecard, credit card, or another type of card. The frequency scannedarray cards described herein refers to components configured to performpassive beam-steering for radars.

Heatsink 302 may be configured to facilitate the transfer of heat fromtransmit antenna assembly 102 to an environment external to transmitantenna assembly 102 and radar assembly 100 (as well as radar assembly200). Heatsink 302 may be in thermal communication with the externalenvironment and the radar assembly 100 or 200, such that the heatdissipates away from radar assembly 100 or 200 to the environment viaconduction through the heat sink. Heatsink 302 may be thermallyinsulated from other components, such that heat does not inadvertentlydissipate to another portion of the radar assembly, in some embodiments.Heatsink 302 may be formed of a material selected based on the thermalconductivity of the material, the environment that the radar is to bedeployed and operate, the material composition of the transmit antennaassembly (and its components), or other criteria. As an example,heatsink 302 may be formed from aluminum or copper. In another example,heatsink 302 may include or be connected to a liquid component, such asa liquid heatsink reservoir, which may be an electrically conductiveliquid (such as water) which may be further insulated from anyelectronic elements, which may be a thermally conductive, electricallynon-conductive liquid (such as a silicon oil) in which the electroniccomponents may be immersed, etc. In some embodiments, transmit antennaassembly 102, as well as, or alternatively, radar assembly 100, mayinclude one or more thermal connectors to heatsink 302. For example, athermal adhesive or paste, copper wires, copper screws and bolts, andthe like, may be used to connect transmit antenna assembly 102 to theexternal environment. Some embodiments may further include Peltieelements and heat pipes thermally disposed between the radar assemblies100 and 200 and the environment. Some embodiments may further takeadvantage of convection in addition to or instead of conduction, such asconnection of heatsink 302 to an environmental convective element (suchas exposure to a windy area or other atmospheric or hydrologicalconvection current) or convective fluid heatsink. In some embodiments,heatsink 302 may be configured to facilitate dissipation of 1 or moreWatts of power, 10 or more Watts of power, 100 or more Watts of power,or other amounts.

While heatsink 302 is depicted as being connected to transmit antennaassembly 102, some embodiments include heatsink 302 being a separatecomponent of radar assembly 100, or a component external to radarassembly 100. For example, heatsink 302 may include thermal connectionsthat connect heatsink 302 to transmit antenna assembly 102 whileheatsink 302 is disposed external to transmit antenna assembly 102.

In some embodiments, active beam-steering circuit 304 may be configuredto control a direction of electromagnetic radiation output by transmitantenna assembly 102. Active beam-steering circuit 304 may include oneor more components that move or actuate another component of transmitantenna assembly 102 to adjust the directionality of the outputelectromagnetic radiation. For example, active beam-steering circuit 304may include one or more motors that are coupled to antenna elements 308and cause antenna elements 308, or a subset of antenna elements 308, toadjust their orientation so as to be directed at a particular locationin space. In some embodiments, active beam-steering circuit 304 may beconfigured to cause a frequency of a component of a source signal to beadjusted such that a corresponding antenna element outputs a portion ofan overall electromagnetic beam that has a desired phase-shift. Somecases include connections, e.g., wires, electrically connecting activebeam-steering circuit 304 to some or all of antenna elements 308 orother antenna elements to cause the output electromagnetic radiation totransmitted therefrom.

In some embodiments, active beam-steering circuit 304 may be configuredto switch between antenna elements to steer an electromagnetic beambeing transmitted by transmit antenna assembly 102. For example, activebeam-steering may include causing a different antenna element or subsetof antenna elements to output electromagnetic radiation having aparticular phase shift so that a resulting electromagnetic beam—formedby combining the electromagnetic radiation output by each antennaelement—is directed towards a target location.

Active beam-steering circuit 304 may be configured to steer theelectromagnetic radiation in various directions along a first dimension.For example, active beam-steering circuit 304 may cause theelectromagnetic radiation to move across a first spatial dimension or asecond spatial dimension. The first spatial dimension and the secondspatial dimension may be orthogonal to one another. For example, thefirst spatial dimension may refer to the azimuthal dimension (e.g.,along an x-y plane) and the second spatial dimension may refer to theelevation dimension (e.g., the y-z plane). Use of the terms “orthogonal”and “perpendicular” and the like does not require that the two spatialdimensions be perfectly perpendicular, as the two dimensions may beseparated by an angle of approximately 90-degrees, e.g., 90-degrees±δ,where δ is a configurable variable having a value between 0-1-degrees,0-5 degrees, or 0-10 degrees. In some cases, the two dimensions arenon-orthogonal.

Active beam-steering circuit 304 may, in some embodiments, be in thermalcommunication with heatsink 302. As active beam-steering circuit 304 maybe the primary (or only) component of transmit antenna assembly 102 thatproduces heat or significant heat, heatsink 302 may function tothermally control heat output of active beam-steering circuit 304. Byhaving the heat producing components of transmit antenna assembly 102,and radar assembly 100, thermally connected to heatsink 302, the heatproduced within transmit antenna assembly 102 may dissipate to theexternal environment without the need for incorporating a form of activecooling to the radar assembly. This may increase the mobility,versatility, and usability of the radar system be eliminating the needto store and apply active cooling means. Even in hot environments (suchas above 35 degrees Celsius) use of heatsink 302 can extend theoperability of active beam-steering circuit 304 or other circuitry, suchas extend transmit time versus cool time in a transmit-cool cycle,increase temperature operability range, etc. In some embodiments,heatsink 302 may provide heat dissipation as long as a thermal gradientis maintained in which the heat is drawn away from the heat producingcomponents of transmit antenna assembly 102, radar assembly 100, etc. Insome embodiments, an active cooling system may be additionally used inextreme environments or under extreme conditions, such as episodicallyif environmental temperature exceeds a temperature limit (for example 40degrees Celsius). In some embodiments, active beam-steering circuit 304may be formed at least partially from a printed circuit board (PCB), andthus the active components of active beam-steering circuit 304 may berestricted to only being disposed on the PCB. Therefore, by thermallyconnecting active beam-steering circuit 304 to heatsink 302, the PCB maybe thermally connected to heatsink 302 such that the heat can dissipateto the external environment.

Transmit antenna assembly 102 may use passive beam-steering circuits 320to steer the electromagnetic radiation along the second spatialdimension. The beam-steering circuits 304 and 320 may cooperate to causethe beam to raster over a volume of space. For instance, if activebeam-steering circuit 304 steer the electromagnetic radiation along theazimuthal dimension, then passive beam-steering circuits 320 may steerthe electromagnetic radiation along the elevation dimension. However,the reverse could also be implemented. Each passive beam-steeringcircuit 320 may include a frequency scanned array card 306 and an arrayof antenna elements 308. As described above, the frequency scanned arraycards can be used to steer a directionality of the outputelectromagnetic radiation by adjusting a frequency of a source signalused to generate a portion of the electromagnetic radiation output by arespective antenna element. In some embodiments, each frequency scannedarray card 306 may include a trace with a length and configuration(e.g., resistance, inductance, and capacitance) is designed toeffectuate a particular operating frequency or phase shift such that arespective portion of the electromagnetic radiation output by thecorresponding antenna element has a desired frequency or phase shift.The superposition of the portions of the electromagnetic radiationgenerated by the antenna elements may determine a direction along agiven axis that the beam is directed towards. As an example, withreference to FIG. 3B, frequency scanning array card 306 may include atrace 318, such as a wire, forming a pattern along which antennaelements 338 are located. The length of trace 318, and the pattern used,effectuate a particular phase shift for a given frequency by delaying asource signal by a specified amount for each of antenna elements 338.Although the pattern of trace 318 is somewhat symmetrical, differenttraces may have patterns that are repeating, non-repeating, symmetrical,asymmetrical, or in other manners. Likewise, antenna elements 338 alongthe pattern of trace 318 are depicted as somewhat symmetrically spaced,but antenna elements 338 can be spaced symmetrically, asymmetrically orin other manners, including on a plurality of traces. Additionally,although antenna elements 338 are depicted as connected to trace 318 inserial, antenna elements 338 can instead or additionally be connected inparallel or hierarchically. For ease of description, one representativeantenna element 338 is depicted per connection to trace 318, which isnot to disclaim that multiple antenna elements 338 connected to trace318 at the same or substantially the same point.

In some embodiments, a quantity of passive beam-steering circuits 320included within transmit antenna assembly 102 may vary depending on theoperating parameters of radar assembly 100. For instance, the number “n”of passive beam-steering circuits 320 may be 1 or more, 10 or more, 50or more, 100 or more, or other values. As each passive beam-steeringcircuit 320 may include (at least) one frequency scanned array card 306and one array of antenna elements 308, the greater the quantity ofpassive beam-steering circuits 320 included within transmit antennaassembly 102, the greater the quantity of frequency scanned array cards306 and antenna elements 308. In some embodiments, the quantity ofpassive beam-steering circuits included within transmit antenna assembly102 may be determined based on the number of antenna elements to beincluded. For example, transmit antenna assembly 102 (as well as receiveantenna assembly 104 or alternatively antenna assembly 202) may includebetween 8 and 64 antenna elements. As an example, with reference to FIG.3C, an antenna assembly, such as transmit antenna assembly 102, mayinclude an array of antenna elements 388 formed of rows and columns ofantenna elements 308. An instance of frequency scanned array card 306may be operatively coupled to antenna elements 308 along a respectivecolumn. Furthermore, active beam-steering circuit 304 may be operativelycoupled along the rows of antenna elements 308 of the array of antennaelements 388. As seen, for example, with reference to FIG. 3D, antennaelements 308 may be separated from one another by a distance d. Distanced may be substantially equal to one half of the wavelength of the output(or received) electromagnetic beam. For example, for a Ku-bandfrequency, distance d may have a value of 0.6-1.3 cm. The combination ofeach component of the output radiation may form an overallelectromagnetic beam that has a direction along a spatial axis definedby an angle θ. The spatial dimension may be the azimuthal or elevationdimension.

Transmit antenna assembly 102 may further include radome 310. Radome 310may include a physical structure used to protect some or all of thecomponents of transmit antenna assembly 102. For example, radome 310 mayprovide protection against environmental contaminates, e.g., rain, snow,ice, dirt, small objects, etc., as well as against possible human,vehicle, animal, or other larger objects, or combinations thereof. Insome embodiments, radome 310 may be formed of a material that minimallyattenuates the electromagnetic radiation output by antenna elements 308.For example, radome 310 may be formed using fiberglass orpolytetrafluoroethylene (PTFE). In some embodiments, radome 310 may notbe included, such as for radar assemblies that do not include movingantenna elements. Furthermore, a shape and size of radome 310 may bedependent on a variety of factors such as the number of antennaelements, the size of the antenna elements, the frequency range of theoutput electromagnetic radiation, a size of an enclosure used to enclosetransmit antenna assembly 102, environmental conditions or otherfactors. For example, the size of radome 310 may be based on a size andshape of transmit antenna assembly 102, receive antenna assembly 104, orradar assembly 100 (or 200). In some cases, for example, transmitantenna assembly 102, receive antenna assembly 104, or radar assembly100 (or 200), may have a volume between 5,000 and 40,000 cm³.

As noted, FIG. 1 illustrates radar assembly 100, which may, in additionto transmit antenna assembly 102, include receive antenna assembly 104.Receive antenna assembly 104 may be constructed in a similar manner astransmit antenna assembly 102, with the exception that receive antennaassembly 104 may be configured to detect portions of the electromagneticradiation output by transmit antenna assembly 102 that reflect offobjects. Receive antenna assembly 104 may detect the reflectedelectromagnetic radiation and may determine features describing theobject from which the electromagnetic radiation reflected.

As an example, FIG. 3E shows receive antenna assembly 104 that mayinclude heatsink 352, active beam-steering circuit 354, passivebeam-steering circuits 360 a-360 m, radome 350, or other components.Passive beam-steering circuits 360 may each include (at least one)frequency scanned array cards 356 and an array of antenna elements 358.For example, passive beam-steering circuit 360 a may include frequencyscanned array card 356 a and an array of antenna elements 358 a (whichmay be one or more antenna elements 358 a as previously described inreference to antenna elements 308), passive beam-steering circuit 360 bmay include frequency scanned array card 356 b and an array of antennaelements 358 b, and passive beam-steering circuit 360 m may includefrequency scanned array card 356 m and an array of antenna elements 358m. For simplicity, as described herein, and unless otherwise specified,the labels “a” to “m” are omitted. The number “m” of passivebeam-steering circuits 360 may be 1 or more, 10 or more, 50 or more, 100or more, or other values. The greater the quantity of passivebeam-steering circuits 360 included within receive antenna assembly 104,the greater the quantity of frequency scanned array cards 356 andantenna elements 358. Furthermore, the value “m” may be the same ordifferent than the value “n.” In some embodiments, a planar (or othertwo-dimensional or quasi-two dimensional) array of antenna elements maybe square-planar (when n=m) or rectangular-planar (e.g., when n≠m). Forinstance, array of antenna elements 388 of FIG. 3C may represent arectangular-planar assembly of antenna elements, which may be used totransmit, receive, or both.

In some embodiments, heatsink 352 and heatsink 302 may be the sameheatsink or different instances of the same type of heatsink, and thedescription above relating to heatsink 302 may be used to describeheatsink 352. For instance, radar assembly 100 may include a singleheatsink that serves to facilitate heat transfer from both transmitantenna assembly 102 and receive antenna assembly 104. In such cases,transmit antenna assembly 102 and receive antenna assembly 104 may bethermally connected to the heatsink. However, alternatively, heatsink302 and heatsink 352 may be different heatsinks that may or may not bethermally connected to one another, as well as to the externalenvironment. Furthermore, heatsink 302 and heatsink 352 may be separateheatsinks that are similarly or differently constructed.

In some embodiments, radome 310 and radome 350 may be the same radome,and the description above relating to radome 310 may be used to describeradome 350. As described in greater detail below, scenarios where radome310 and radome 350 are the same single radome may correspond to someembodiment whereby the antenna elements of both antenna assemblies areshared. For instance, radar assembly 200 of FIG. 2 includes antennaassembly 202 whereby the antenna elements used to form the transmitantenna are the same as the antenna elements used to form the receiveantenna. However, in some embodiments, radome 310 and radome 350 may beseparate radomes formed in a same or different manner.

Active beam-steering circuit 354 may be substantially similar to activebeam-steering circuit 304, with the exception that active beam-steeringcircuit 354 may be configured to control a direction with which receiveantenna assembly 104 detects reflected electromagnetic radiation. Forexample, instead of controlling the direction of the outputelectromagnetic radiation from the that antenna elements, activebeam-steering circuit 354 may control a direction of the detected(reflected) electromagnetic radiation. The reflected electromagneticradiation may result from the output electromagnetic radiation beingincident on an object, reflecting off that object, and traveling in anopposite direction back towards the radar. In some embodiments, activebeam-steering circuit 354 may operate in conjunction with activebeam-steering circuit 304 such that the antenna elements of bothcircuits 304 and 354 are operated in parallel, e.g., within 1 second ofone another, within 1 millisecond of one another, within 1 nanosecond ofone another, at substantially the same time, etc. In some embodiments,active beam-steering circuit 354 may operate in conjunction with activebeam-steering circuit 304 such that the antenna elements of bothcircuits 304 and 354 are operated in a physical relationship, e.g.,within 1 degree of one another, within 1 arcminute of one another,within 1 arcsecond of one another, at substantially the same angle, etc.This may allow the antenna elements to be oriented such that thereflected electromagnetic beam is easier to detect. Still further, someembodiments include a single active beam-steering circuit that isconfigured to control the directionality of the antenna elements forboth transmit and receive operations. A single active beam-steeringcircuit may control the orientation of the antenna elements in batches(e.g., antenna elements 308 together and antenna elements 358 together,antenna elements along a row together whether those antenna elements areantenna elements 308 or antenna elements 358, etc.).

Passive beam-steering circuits 360 may also be substantially similar topassive beam-steering circuits 320, with the exception that passivebeam-steering circuits 360 may be configured to control a direction fromwhich receive antenna assembly 104 detects the reflected electromagneticradiation. The direction that passive beam-steering circuits 360 controlmay be along a spatial dimension (which may be an angular dimension)different from the direction that active beam-steering circuit 354controls. For example, active beam-steering circuit 354 may control thedirectionality of the detected reflected electromagnetic radiation alongan azimuth dimension, whereas passive beam-steering circuits 360 maycontrol the directionality of the detected reflected electromagneticradiation along an elevation dimension.

Each passive beam-steering circuit 360 may include a frequency scannedarray card 356 and an array of antenna elements 358. Frequency scannedarray cards 356 may be configured similarly to frequency scanned arraycards 306. In particular, frequency scanned array cards 356 may beconfigured to receive the reflected electromagnetic radiation, apply areverse phase-shift, combine the resulting signals, and output thecombined signal which can be used to infer information regarding thedetected object (if any objects are detected). Thus, the functionalityof frequency scanned array cards 356 may be substantially similar tothat of frequency scanned array cards 306, with the exception thatfrequency scanned array cards 356 may operate during receive operations.Furthermore, some embodiments include frequency scanned array cards 306and frequency scanned array cards 356 being the same set of frequencyscanned array cards capable of steering the (transmitted)electromagnetic beam and receiving the (received) reflectedelectromagnetic beam.

In some embodiments, antenna elements 358 may be the same or similar toantenna elements 308, with the exception that antenna elements 358 maybe configured to operate in “receive” mode whereby they detect reflectedelectromagnetic radiation, e.g., the electromagnetic radiation thatreflects off of an object and is transmitted back towards the source.The number of antenna elements 358 may be the same or different thanthat of antenna elements 308. In some embodiments, a single set ofantenna elements may be used for both transmission and reception asdescribed in greater detail below with reference to FIG. 2.

As shown in FIG. 1, isolation component 106 may be configured to isolatetransmit antenna assembly 102 from receive antenna assembly 104. In someembodiments, isolation component 106 may be a radio frequency (RF)isolator. In other words, isolation component 106 operates to ensurethat the electromagnetic radiation output by transmit antenna assembly102 is isolated from the electromagnetic radiation detected by receiveantenna assembly 104. Doing so can prevent the receive elements fromdetecting signal output directly from the transmit elements, withoutreflecting off any objects.

Isolation component 106, e.g., an RF isolator, may refer to a devicewhich isolates the receive antenna from signals emitted by the transmitantenna, including signals which may travel along electrical,communication, and other connections. Such a device may include twoports that transmit electromagnetic radiation in a single direction. Insome embodiments, isolation component 106 may be a “non-reciprocal”device that applies a phase shift to power entering one of the ports toallow the phase-shifted power to be absorbed. The other port may beconfigured to transmit all of the power. Isolation component 106 may bea terminator circulator, a Faraday rotation isolator, afield-displacement isolator, or a resonance isolator. Isolationcomponent 106 may be formed of a ferromagnetic material, such asmagnetite (Fe₃O₄).

In some embodiments, isolation component 106 may refer to a device whichisolates the receive antenna from signals emitted by the transmitantenna which may be transmitted through atmosphere or another medium(e.g., be un-reflected or via a direct path) or which may be reflectedby one or more components of radar assembly 100 itself. Such anisolation component may consist of one or more materials which absorb orotherwise dampen transmitted signals, including metal materials such asaluminum or copper. In some embodiments, isolation component 106 may bea component which physically surrounds a receive antenna or sides of areceive antenna from direct transmission or self-reflected components.For example, isolation component 106 may be a Faraday cage orquasi-Faraday cage that blocks direct transmission paths between atransmit antenna and a receive antenna. In some embodiments, isolationcomponent 106 may have an aperture or opening (including an aperturewith a lens, filter, etc.) which allows transmission of reflectedsignals (e.g., reflected from objects within the scanned volume) whileblocking transmission of direct signals. Isolation component 106 may becomposed of a conductive material or mesh, where the material of theisolation component 106 may be conductive in the Ku-band and insulatingin other parts of the EM spectrum.

In some embodiments, frequency conversion component 108 may beconfigured to take incoming power of a certain frequency and convert itinto power of another frequency. As an example, frequency conversioncomponent 108 may receive an incoming signal having a first frequency,e.g., 60 Hz, and convert the signal into a signal having a secondfrequency, e.g., 400 Hz. Frequency conversion component 108 may also bereferred to herein interchangeably as a frequency converter. Someexample types of frequency conversion components include rotaryfrequency converters and solid-state frequency converters. Rotaryfrequency converters use electrical energy to drive a motor, whereassolid-state frequency convertors may perform an AC to DC conversion.

Frequency conversion component 108 may operate to change a frequency ofa signal by combining or mixing other frequencies. In particular,frequency conversion component 108 may implement a technique referred toas “heterodyning,” where a signal in one frequency range is shifted toanother frequency range. For example, given two signals, two new signalsmay be created therefrom by determining the summation and difference ofthe two new signals, which are referred to as “heterodynes.” Someexamples for using frequency conversion include shifting a signal fromone frequency band to another frequency band.

Power distribution component 110 may be configured to control an amountof power distributed to other components of radar assembly 100 (or 200).For example, power distribution component 110 may be configured togenerate and provide electrical power to active beam-steering circuits304, 354. Some example types of power distribution components include acentralized power supply, a distributed power supply, or a layered andfused power supply. Centralized power supplies may include componentsfor rectification, filtering, step-down and voltage stabilization thatare distributed in a unit. Due to its low cost and ease of use,centralized power supplies are often used by low power radar assemblies.Distributed power supplies have each load corresponding to a separatepower supply system. Together, the separate power supply systems formthe distributed power supply. Layered and fused power supplies mayinclude a centralized rectification and decentralized voltagestabilization.

Computing system 112 may include components such as memory storing data,program instructions, or other information, interfaces, processors, orother components. As an example, computing system 112 may include agraphics processing unit (GPU). Computing system 112 may be configuredto control the operations of each component of radar assembly 100. Forexample, computing system 112 may instruct power distribution component110 to generate a signal to be provided to transmit antenna assembly 102for effectuating the phase shift imparted by each portion of the outputelectromagnetic radiation. A more detailed example of the componentsincluded by computing system 112 is provided below with reference toFIG. 10.

As shown in FIG. 2, radar assembly 200 may be substantially similar toradar assembly 100 with the exception that radar assembly 200 includes asingle antenna assembly 202 and T/R module 220 (including multiple T/Rmodules as previously described), as opposed to transmit antennaassembly 102 and receive antenna assembly 104. As an example, withreference to FIG. 3F, antenna assembly 202 may include heatsink 370,active beam-steering circuit 374, passive beam-steering circuits 380,e.g., passive beam-steering circuits 380 a, 380 b, . . . , 380 n, radome390, or other components. Heatsink 370 and radome 390 may besubstantially similar to heatsink 302 and radome 310 of transmit antennaassembly 102, and the previous description may apply. Activebeam-steering circuit 374 may be substantially similar to activebeam-steering circuit 304 and active beam-steering circuit 354, with theexception that active beam-steering circuit 374 may facilitate bothtransmit and receive operations. Passive beam-steering circuits 380 maybe substantially similar to passive beam-steering circuits 320 and 360,with the exception that passive beam-steering circuit 380 may facilitateboth transmit and receive operations. Each passive beam-steering circuit380 may include a frequency scanned array card 376, e.g., frequencyscanned array card 376 a, 376 b, . . . , 376 n, and an array of antennaelements 378 e.g., arrays of antenna elements 378 a, 378 b, . . . , 378n (for which a representative antenna element 378 a, 378 b, 378 c isdepicted and which may contain one or more antenna elements 378).Frequency scanned array card 376 may be substantially similar tofrequency scanned array cards 306 and 356, as it can facilitate passivephase-shifting to control a direction of transmitted electromagneticradiation and detectable reflected electromagnetic radiation. Antennaelements 378 may be substantially similar to antenna elements 308 and358, and may facilitate transmission of electromagnetic radiationdirected at a location in space as well as reception of any reflectedelectromagnetic radiation from objects located in a volume in spacespecified by the location.

T/R modules or switches may be used in active beam-steering circuit 374to enable antenna elements 378 to operate in both transmit and receivemodes. T/R modules may be used to boost output power of theelectromagnetic radiation transmitted by radar assembly 200, identify abaseline noise spectrum for receive operations, and may further providecontrol for steering the electromagnetic radiation, e.g., beam-steering.T/R modules may be sized to fit within the array of antenna elements,e.g., antenna elements 378, and may have a size that is related to thewavelength of the system. For example, a system operating at 18 GHz mayinclude a T/R module having a size 0.835 cm in a dimension,corresponding to the wavelength of the 18 GHz system.

T/R module 220 may enable operations in both transmit and receiveoperations for antenna assembly 202 may occur within 1 second of oneanother, within 1 millisecond of one another, within 1 nanosecond of oneanother, etc.; however this is not a requirement. T/R module 220 mayinclude a duplexer, a signal isolator, a limiter, a low-noise amplifier,a phase shifter, a high-power amplifier, an attenuator, a powerconditioner, modulation circuitry, a capacitor or other charge storagedevice, beam-steering circuitry, or other components. Various of theseelements may also be present in transmit antenna assembly 102 or receiveantenna assembly 104, including as components of active beam-steeringcircuit 304 (or 354).

The duplexer allows antenna elements 378 to be used for both transmitand receive operations. The duplexer may be formed from a ferromagneticmaterial and in some cases may be disposed outside of the T/R module'senclosure. The isolator may be used to match the load to antennaelements 378 and prevent power degradation. The limiter may preventdamage to the low-noise amplifier during transmit operations, as well asat other times when there is additional radiation. The limiter may alsobe used to absorb reflected power occurring during transmission. Thereflected power here differs from the reflected electromagneticradiation, as this refers to internal reflection or more generallyreflection not due to the output electromagnetic radiation reflectingoff an object in a target location external to radar assembly 200. Thelow-noise amplifier may be configured to minimize attenuation of longtransmission lines, provide good impedance matching, and may providetermination so that the isolator can be removed (if desired). The phaseshifter may apply a desired phase shift to a given component of theelectromagnetic radiation output by antenna elements 378 duringtransmissions and may also provide phase-shifting for the reflectedelectromagnetic radiation detected by antenna elements 378. Thehigh-power amplifier may be configured to amplify the power of thetransmitted electromagnetic radiation, the power of the receivedelectromagnetic radiation, or both. The attenuator may be used to reducea magnitude of the sidelobes of the received electromagnetic radiationand can also be used to minimize the sidelobes of the transmittedelectromagnetic radiation. The power conditioner may be used to “clean”the power such that excess voltage within the system is reduced. Themodulation circuitry may be used to switch T/R modules from operating intransmit mode to operating in receive mode, and vice versa. Themodulation circuitry may do so quickly by turning off the transmit gainpath during receive operations, and by biasing off the receive amplifierpath during transmit operations. The charge storage device, e.g., acapacitor, may be used to store charges to be used to maintain theamplified bias voltage. The beam-steering circuitry may be used tocontrol an amount of phase shift to be applied to each component of theelectromagnetic radiation produced by (during transmit or receive)antenna elements 378.

While T/R modules 220 can be used by radar assembly 200 to allow for acombined transmit/receive antenna assembly, e.g., antenna assembly 202,T/R modules 220 can increase the complexity of the circuitry used tofabricate radar assembly 200. Furthermore, the power of the transmittedelectromagnetic radiation may need to be increased relative to the powerneeded for a stand-alone transmit antenna assembly, e.g., transmitantenna assembly 102. Therefore, the use of T/R modules 220 may dependon the constraints of the system and manufacturer.

FIG. 4 illustrates an example use case of radar assembly 100 or 200, inaccordance with one or more embodiments. In example 400, radar assembly100, 200 may be configured to transmit electromagnetic radiation 404 ain a first direction. Radar assembly 100, 200, as mentioned above, maysteer electromagnetic radiation 404 a such that it is directed to alocation in physical space where a determination can be made as towhether any objects are located in a volume associated with thatlocation. If an object is located in that volume, such as object 402 a,then electromagnetic radiation 404 a may reflect off of object 402 a.For instance, reflected electromagnetic radiation 406 a may result fromelectromagnetic radiation 404 a reflecting off object 402 a. In someembodiments, radar assembly 100, 200 may be configured to adjust adirection that electromagnetic radiation 404 a is directed towards. Forexample, radar assembly 100, 200 may steer the electromagnetic radiation(actively, passively, or a combination of both actively and passively)to be directed towards another location in physical space to determinewhether any objects are located within another volume associated withthe new location. Radar assembly 100, 200 may also be configured todetermine whether objects detected in the new location's volume are thesame as the objects detected within the previous location's volume. Asan example, radar assembly 100, 200 may steer electromagnetic radiation404 b to be output in a direction different from the direction thatelectromagnetic radiation 404 a is in. In some embodiments,electromagnetic radiation 404 b may determine whether any objects arelocated in the volume associated with the steered location. If an objectis located in that volume, such as object 402 b, then electromagneticradiation 404 b may reflect off object 402 b and reflect back, e.g.,reflected electromagnetic radiation 406 b, towards radar assembly 100,200.

Based on the reflected electromagnetic radiation 406 a, 406 b, radarassembly 100, 200 may be configured to determine whether object 402 a isthe same object as object 402 b. If so, radar assembly 100, 200 maydetermine characteristics of the object, such as a size, shape,velocity, acceleration, etc. Furthermore, if object 402 a and object 402b are different from one another, radar assembly 100, 200 may determineseparate features relating to objects 402 a and 402 b.

In some embodiments, radar assembly 100, 200 may be configured todetermine a range of an object based on the round-trip time delaybetween signal transmission and receipt of the reflected signal. In someembodiments, radar assembly 100, 200 may estimate an angular location ofa detected object based the direction of the transmit beam and receivebeam when the object was detected. In some embodiments, radar assembly100, 200 may estimate the angular location of a detected target based onconstructive and destructive interference of the reflected signaldetected at different locations on the receiver antenna assembly or ondifferent antenna elements of the receiver antenna assembly. In someembodiments, radar assembly 100, 200 may be configured to determine arange rate of an object based on measurement of the frequency shift(e.g., Doppler shift) between the transmit signal and the reflectedreceive signal.

Radar assembly 100, 200 may scan a volume of space in an orderly manner,in a random manner, may scan along a predicted track of a previouslyidentified object, etc. Radar assembly 100, 200 may scan alongsubstantially all elements in a first direction and then adjust aposition (using active or passive beam-steering) in a second directionand then scan again along substantially all elements in the firstdirection. For example, radar assembly 100, 200 can operate in a rasterscan or quasi-raster scan, interlaced scan, sweep scan, etc. In someembodiments, radar assembly 100, 200 can operate in multiple scan modes,including based on whether or not an object has been detected. Forexample, radar assembly 100, 200 may track an object once it is detected(such as an object larger than a size threshold, moving faster than avelocity threshold, etc.). In some embodiments, radar assembly 100, 200may track an object until it disappears from a field of view or fallsbelow a threshold (e.g., size, speed). In some embodiments, radarassembly 100, 200 may search near a detected object to locate otherobjects which may accompany the first object. In some embodiments, radarassembly 100, 200 may search near a position or last known position ofan object which disappears or is no longer detected.

FIG. 5 illustrates an example architecture for array 500 of antenna T/Rsub-arrays 502 in a transmit and receive radar assembly. Array 500 maybe an architecture of radar assembly 200. Array 500 is comprised ofantenna T/R sub-arrays 502. Antenna T/R sub-arrays 502 may be organizedin a planar or quasi-planar array, such that antenna T/R sub-arrays 502are located along a first direction (for example a row) and along asecond direction (for example a column). Antenna T/R sub-arrays 502 mayfunction as individual transmitter antenna and receiver antennas. Whentransmitting, antenna T/R sub-arrays 502 may receive one or moretransmission signal (or signal corresponding to a signal to betransmitted) from T/R signal processing unit 510. T/R signal processingunit 510 may receive signals from or be in communication withtransmitted from computing system 112, frequency conversion component108, power distribution component 110, T/R module 220, etc. Thetransmission signal output by T/R signal processing unit 510 may be adigital signal and may input into D/A converter 508. Alternatively, T/Rsignal processing unit 510 may output an analog signal or contain withinitself a D/A converter. The output from D/A converter 508 (oralternatively from T/R signal processing unit 510 may be input to an upconverter 512 that may use the output from a local oscillator (LO) 514.T/R signal processing unit 510 may correspond to at least one,substantially one, exactly one, multiple, etc. D/A converters 508 and upconverters 512. D/A converter 508 and up converter 512 are depicted asoperating on an output signal from T/R signal processing unit 510, butcan instead operate on multiple (including multiplexed) signals outputby T/R signal processing unit 510.

When receiving, antenna T/R sub-arrays 502 may transmit one or morereceived signals (or signal generated as a result of a received signal)to down converter 504 that may use the output from a local oscillator(LO) 516. Each of the antenna T/R sub-arrays 502 may correspond to atleast one, substantially one, exactly one, etc. down converter 504.After the received signal is down converted 504, it may be input intoA/D converter 506. Each of the antenna T/R sub-arrays 502 or downconverter 504 may correspond to at least one, substantially one, exactlyone, etc. A/D converter 506. Alternatively, received signals from eachof the antenna T/R sub-arrays 502 can be batched or multiplexed and fedinto one or more A/D converter 506. The received signal is then outputto T/R signal processing unit 510.

FIG. 6 illustrates an example antenna T/R sub-array 502. The entirecollection of sub-arrays 502 within 500 may provide an implementation ofactive beam-steering circuit 374 and a plurality of passivebeam-steering circuits 380 within antenna assembly 202. Antenna T/Rsub-array 502 is provided to illustrate an example of antenna T/Rsub-array components, which is not to say that other architectures areprohibited. Antenna T/R sub-array 502 is depicted as comprising antennaelements 616 a-616 n and antenna elements 616 b-616 m. Antenna elements616 may correspond to antenna elements 378 of FIG. 3F, where antennaelements 616 a-616 n may correspond to antenna elements 378 a, antennaelements 616 b-616 m may correspond to antenna elements 378 b, etc.Antenna T/R sub-array 502 comprises one or more switches 602, 608, and614. Switches 602, 608, and 614 function in tandem to ensure thatantenna T/R sub-array 502 operates in either transmit or receive mode.In transmit mode, antenna T/R sub-array 502 receives an RF signal, heredepicted as RFin 622. RFin 622 may be output by T/R signal processingunit 510 and processed or altered by one or more intervening circuitelements. RFin 622 may be split along one or more parallel transmissionlines, where each transmission line may correspond to a frequencyscanned array of antenna elements 616 (e.g., antenna elements 616 a-616n, antenna elements 616 b-616 m, etc. and where antenna elements 616a-616 n may correspond to a first transmission line, antenna elements616 b-616 m may correspond to a second transmission line, etc.). RFin622 may be input to one or more of the one or more switches 602 for eachof the one or more transmission lines. In transmit mode, RFin 622 may bephase shifted by phase shifter 604 or attenuated by variable attenuator606. RFin 622 may be differently phase shifted by phase shifter 602 ordifferently attenuated by variable attenuator 606 for each transmissionline. After RFin 622 is phase shifted or attenuated, RFin 622 may beinput into one or more switches 608. In transmit mode, switch 608 mayroute RFin 622 to power amplifier 612. In transmit mode, switch 614 maythen route RFin 622 to a frequency scanned array of antenna elements616. The path of RFin 622 in transmit mode may be depicted by the routecorresponding to arrows pointing towards antenna elements 616. Althoughthree switches are depicted for a transmission line (e.g., one or moreswitches 602, one or more switches 608, and one or more switches 614),more or fewer switches may be present. For example, each antenna element616 may include or be in communication with a dedicated switch, eachcolumn may be associated with a switch, each row may be associated witha switch, etc. Antenna elements 616 are depicted for each transmissionline, where each transmission line may have one or more antenna elements616, the same number of antenna elements 616, different numbers ofantenna elements 616, etc.

The frequency scanned array of antenna elements 616 measures a receivedsignal, here depicted as RFout 620. From the array of antenna elements616, RFout 620 is input into one or more switches 614. The one or moreswitched 614 may then route RFout 620 to low noise amplifier 610. Thepath of RFout 620 in receive mode may be depicted by the routecorresponding to arrows pointing away from antenna elements 616. In someembodiments, other low noise filtering circuitry can be used instead orin addition to low noise amplifier 610. From low noise amplifier 610,RFout 620 may be input into one or more switch 608. From one or moreswitches 608, RFout 620 can be input into variable attenuator 606 orphase shifter 604. In some embodiments, phase shifter 604 and variableattenuator 606 can operate symmetrically, selectively, or asymmetricallyon signals (e.g., RFin 622 or RFout 620). For example, variableattenuator 606 may operate on RFout 620 and may not operate on RFin 622(or on RFin 622 in some instances). From phase shifter 604, RFout 620corresponding to one or more transmission lines may be summed bysummation operator 618. Alternatively, RFout 620 corresponding to one ormore transmission lines may be multiplexed. RFout 620 may then be outputor otherwise communicated to T/R signal processing unit 510.

FIG. 7 illustrates an example architecture for array 700 of receiverantenna sub-arrays 702 and transmitter antenna sub-arrays 722. Array 700may be an architecture of radar assembly 100. Array 700 is comprised ofreceiver antenna sub-arrays 702 and transmitter antenna sub-arrays 722.Receiver antenna sub-arrays 702 and transmitter antenna sub-arrays 722may be organized in a planar or quasi-plana array, such that receiverantenna sub-arrays 702 and transmitter antenna sub-arrays 722 arelocated along a first direction (for example a row) and along a seconddirection (for example a column). Receiver antenna sub-arrays 702 andtransmitter antenna sub-arrays 722 are depicted as being arranged in ablock of receiver antenna sub-arrays 702, which extends in both a firstdirection and a second direction, and a block of transmitter antennasub-arrays 722, which also extends in both a first direction and asecond direction. As depicted, the set of receiver antenna sub-arrays702 is adjacent to the set of transmitter antenna sub-arrays 722, suchthat each row of array 700 contains receiver antenna sub-arrays 702 andtransmitter antenna sub-arrays 722 while columns of the array 700contain either receiver antenna sub-arrays 702 or transmitter antennasub-arrays 722. However, the arrangement of receiver antenna sub-arrays702 and transmitter antenna sub-arrays 722 may be different, includingco-planar, offset, interstitial, three-dimensional, etc. In someembodiments, receiver antenna sub-arrays 702 and transmitter antennasub-arrays 722 are interspersed or co-planar or substantially co-planar.Receiver antenna sub-arrays 702 and transmitter antenna sub-arrays mayoccupy the same or different (e.g., alternating) positions in a firstdirection (e.g., row) and a second direction (e.g., column). Array 700may contain the same or a different number of receiver antennasub-arrays 702 and transmitter antenna sub-arrays 722.

Receiver antenna sub-arrays 702 may receive at the same time (or atsubstantially the same time) as transmitter antenna sub-arrays 722transmit. Receiver antenna sub-arrays 702 may operate to receive signalsat substantially all times, in intervals, at substantially the sametimes, at different times, etc. Transmitter antenna sub-arrays 722 mayoperate to transmit signals at substantially the same time, atsubstantially the same time for transmitter antenna sub-arrays 722 of afirst direction, at substantially the same time for transmitter antennasub-arrays 722 of a second direction, etc. In some embodiments, receiverantenna sub-arrays 702 or transmitter antenna sub-arrays 722 may cyclethrough active receive/transmit phases and rest or off phases. Whenreceiving, receiver antenna sub-arrays 702 output a received signal (orsignal corresponding to a received signal) to circuitry which mayinclude or operate as a down converter 704 utilizing a local oscillator(LO) 730 or other frequency source. Each receiver antenna sub-array 702may correspond to substantially one down converter 704, which may outputthe received signal to A/D converter 706. Each down converter 704 maycorrespond to substantially one A/D converter 706. For received signalswhich are phase shifted, output of receiver antenna sub-arrays 702 maybe summed or multiplexed and passed through less than one down converter704 (or A/D converter 706). From A/D converter, received signals areinput to a receiver signal processing unit 710.

When transmitting, a transmitter signal processing unit 720 transmits asignal for transmission (or a signal that corresponds to a signal to betransmitted). The transmission signal is input into D/A converter 708for conversion into an analog signal. Alternatively, the transmittersignal processing unit 720 may contain a D/A converter or output ananalog signal. The transmission signal is input into up converter 712 orother circuitry which may include or operate as an up converterutilizing a local oscillator (LO) 730 or other frequency source. Upconverter 712, like down converter 704, may also receive as input apower source, control voltage, etc. From up converter 712, thetransmission signal is input into transmitter antenna sub-arrays 722.Transmitter antenna sub-arrays 722 may receive the same signal, portions(such as selected by one or more switches) of the same signal,demultiplexed portions of the same signal, etc. Transmitter signalprocessing unit 720 may correspond to one or more D/A converters 708 orone or more up converters 712.

In some embodiments, receiver signal processing unit 710 and transmittersignal processing unit 720 may be in communication or may be the sameunit. Receiver signal processing unit 710 and transmitter signalprocessing unit 720 may be different from a T/R signal processing unit,such as T/R signal processing unit 510, in that they may not includecontrol circuitry or generate signals to switch one or more antenna T/Rsub-array (such as antenna T/R sub-array 502) between transmission andreception modes.

FIG. 8 illustrates an example transmitter sub-array 722. The entirecollection of sub-arrays 722 within 700 provide an implementation of anactive beam-steering circuit 304 and a plurality of passivebeam-steering circuits 320 within transmit antenna assembly 102. Antennatransmitter sub-array 722 is provided to illustrate an example ofantenna transmitter sub-array components, which is not to say that otherarchitectures are prohibited. Antenna transmitter sub-array 722 isdepicted as comprising antenna elements 816 a-816 n and antenna elements816 b-816 m. Antenna elements 816 may correspond to antenna elements 308of FIG. 3A, where antenna elements 816 a-816 n may correspond to antennaelements 308 a, antenna elements 816 b-816 m may correspond to antennaelements 308 b, etc. Transmitter sub-array 722 receives an RF signal,here depicted as RFin 822. RFin 822 may be output by a T/R signalprocessing unit or by a transmitter signal processing unit, such astransmitter signal processing unit 720, and processed or altered by oneor more intervening circuit elements. RFin 822 may be split along one ormore parallel transmission lines, where each transmission line maycorrespond to a frequency scanned array of antenna elements 308. RFin822 may be controlled by one or more switches, including switches whichselect one or more of the one or more transmission lines. RFin 822 maybe phase shifted by phase shifter 804 or attenuated by variableattenuator 806. RFin 822 may be differently phase shifted by phaseshifter 804 or differently attenuated by variable attenuator 806 foreach transmission line. RFin 822 may then be amplified by poweramplifier 812 prior to transmission through the frequency scanned arrayof antenna elements 816. Antenna elements 816 (e.g., antenna elements816 a-816 n, antenna elements 816 b-816 m, etc. and where antennaelements 816 a-816 n may correspond to a first transmission line,antenna elements 816 b-816 m may correspond to a second transmissionline, etc.) are depicted for each transmission line, where eachtransmission line may have one or more antenna element 816, the samenumber of antenna elements 816, different numbers of antenna elements816, etc.

FIG. 9 illustrates an example receiver sub-array 702. The entirecollection of sub-arrays 702 within 700 provide an implementation of anactive beam-steering circuit 354 and a plurality of passivebeam-steering circuits 360 within receive antenna assembly 104. Antennareceiver sub-array 702 is provided to illustrate an example of antennareceiver sub-array components, which is not to say that otherarchitectures are prohibited. Antenna receiver sub-array 702 is depictedas comprising antenna elements 916 a-916 n and antenna elements 916b-916 m. Antenna elements 916 may correspond to antenna elements 358 ofFIG. 3E, where antenna elements 916 a-916 n may correspond to antennaelements 358 a, antenna elements 916 b-916 m may correspond to antennaelements 358 b, etc. A frequency scanned array of antenna elements 916measures a received signal, here depicted as RFout 920. Antenna elements916 (e.g., antenna elements 916 a-916 n, antenna elements 916 b-916 m,etc. and where antenna elements 916 a-916 n may correspond to a firsttransmission line, antenna elements 916 b-916 m may correspond to asecond transmission line, etc.) are depicted for each transmission line,where each transmission line may have one or more antenna element 916,the same number of antenna elements 916, different numbers of antennaelements 916, etc. From the array of frequency scanned antenna element916, RFout is input into low noise amplifier 910. In some embodiments,other low noise filtering circuitry can be used instead or in additionto low noise amplifier 910. From low noise amplifier 910, RFout 920 maybe input into variable attenuator 906 and phase shifter 904. From phaseshifter 904, RFout 920 corresponding to one or more transmission linesmay be summed by summation operator 918. Alternatively, RFout 920corresponding to one or more transmission lines may be multiplexed.RFout 920 may then be output or otherwise communicated to T/R signalprocessing unit or a receiver signal processing unit, such as receiversignal processing unit 710.

FIG. 10 is a diagram that illustrates an exemplary computing system 1000in accordance with embodiments of the present technique. Variousportions of systems and methods described herein, may include or beexecuted on one or more computing systems similar to computing system1000. Further, processes and modules described herein may be executed byone or more processing systems similar to that of computing system 1000.For example, computing system 112 may execute operations using aprocessing system that is the same or similar to computing system 1000.

Computing system 1000 may include one or more processors (e.g.,processors 1010-1-1010-N) coupled to system memory 1020, an input/output(I/O) device interface 1030, and a network interface 1040 via aninput/output (I/O) interface 1050. A processor may include a singleprocessor or a plurality of processors (e.g., distributed processors). Aprocessor may be any suitable processor capable of executing orotherwise performing instructions. A processor may include a centralprocessing unit (CPU) that carries out program instructions to performthe arithmetical, logical, and input/output operations of computingsystem 1000. A processor may execute code (e.g., processor firmware, aprotocol stack, a database management system, an operating system, or acombination thereof) that creates an execution environment for programinstructions. A processor may include a programmable processor. Aprocessor may include general or special purpose microprocessors. Aprocessor may receive instructions and data from a memory (e.g., systemmemory 1020). Computing system 1000 may be a uni-processor systemincluding one processor (e.g., processor 1010-1), or a multi-processorsystem including any number of suitable processors (e.g.,1010-1-1010-N). Multiple processors may be employed to provide forparallel or sequential execution of one or more portions of thetechniques described herein. Processes, such as logic flows, describedherein may be performed by one or more programmable processors executingone or more computer programs to perform functions by operating on inputdata and generating corresponding output. Processes described herein maybe performed by, and apparatus can also be implemented as, specialpurpose logic circuitry, e.g., an FPGA (field programmable gate array)or an ASIC (application specific integrated circuit). Computing system1000 may include a plurality of computing devices (e.g., distributedcomputing systems) to implement various processing functions.

I/O device interface 1030 may provide an interface for connection of oneor more I/O devices 1002 to computing system 1000. In some embodiments,I/O devices may include antenna assemblies, such as transmit antennaassembly 102, receive antenna assembly 104, or transmit/receive antennaassembly 202. I/O devices may include devices that receive input (e.g.,from a user) or output information (e.g., to a user). I/O devices 1002may include, for example, graphical user interface presented on displays(e.g., a cathode ray tube (CRT) or liquid crystal display (LCD)monitor), pointing devices (e.g., a computer mouse or trackball),keyboards, keypads, touchpads, scanning devices, voice recognitiondevices, gesture recognition devices, printers, audio speakers,microphones, cameras, or the like. I/O devices 1002 may be connected tocomputing system 1000 through a wired or wireless connection. I/Odevices 1002 may be connected to computing system 1000 from a remotelocation. I/O devices 1002 located on remote computer system, forexample, may be connected to computing system 1000 via a network, e.g.,network(s) 1060, and network interface 1040.

Network interface 1040 may include a network adapter that provides forconnection of computing system 1000 to a network. Network interface 1040may facilitate data exchange between computing system 1000 and otherdevices connected to the network. Network interface 1040 may supportwired or wireless communication. The network, such as for examplenetwork(s) 1060, may include an electronic communication network, suchas the Internet, a local area network (LAN), a wide area network (WAN),a cellular communications network, or the like.

System memory 1020 may be configured to store program instructions 1022or data 1024. Program instructions 1022 may be executable by a processor(e.g., one or more of processors 1010-1-1010-N) to implement one or moreembodiments of the present techniques. Program instructions 1022 mayinclude modules of computer program instructions for implementing one ormore techniques described herein with regard to various processingmodules. Program instructions may include a computer program (which incertain forms is known as a program, software, software application,script, or code). A computer program may be written in a programminglanguage, including compiled or interpreted languages, or declarative orprocedural languages. A computer program may include a unit suitable foruse in a computing environment, including as a stand-alone program, amodule, a component, or a subroutine. A computer program may or may notcorrespond to a file in a file system. A program may be stored in aportion of a file that holds other programs or data (e.g., one or morescripts stored in a markup language document), in a single filededicated to the program in question, or in multiple coordinated files(e.g., files that store one or more modules, sub programs, or portionsof code). A computer program may be deployed to be executed on one ormore computer processors located locally at one site or distributedacross multiple remote sites and interconnected by a communicationnetwork.

System memory 1020 may include a tangible program carrier having programinstructions stored thereon. A tangible program carrier may include anon-transitory computer readable storage medium. A non-transitorycomputer readable storage medium may include a machine-readable storagedevice, a machine-readable storage substrate, a memory device, or anycombination thereof. Non-transitory computer readable storage medium mayinclude non-volatile memory (e.g., flash memory, ROM, PROM, EPROM,EEPROM memory), volatile memory (e.g., random access memory (RAM),static random access memory (SRAM), synchronous dynamic RAM (SDRAM)),bulk storage memory (e.g., CD-ROM and/or DVD-ROM, hard-drives), or thelike. System memory 1020 may include a non-transitory computer readablestorage medium that may have program instructions stored thereon thatare executable by a computer processor (e.g., one or more of processors1010-1-1010-N) to cause the subject matter and the functional operationsdescribed herein. A memory (e.g., system memory 1020) may include asingle memory device and/or a plurality of memory devices (e.g.,distributed memory devices). Instructions or other program code toprovide the functionality described herein may be stored on a tangible,non-transitory computer readable media. In some cases, the entire set ofinstructions may be stored concurrently on the media, or in some cases,different parts of the instructions may be stored on the same media atdifferent times.

I/O interface 1050 may be configured to coordinate I/O traffic betweenprocessors 1010-1-1010-N, system memory 1020, network interface 1040,I/O devices 1002, and/or other peripheral devices. I/O interface 1050may perform protocol, timing, or other data transformations to convertdata signals from one component (e.g., system memory 1020) into a formatsuitable for use by another component (e.g., processors 1010-1-1010-N).I/O interface 1050 may include support for devices attached throughvarious types of peripheral buses, such as a variant of the PeripheralComponent Interconnect (PCI) bus standard or the Universal Serial Bus(USB) standard.

Embodiments of the techniques described herein may be implemented usinga single instance of computing system 1000 or multiple computing systems1000 configured to host different portions or instances of embodiments.Multiple computing systems 1000 may provide for parallel or sequentialprocessing/execution of one or more portions of the techniques describedherein.

Those skilled in the art will appreciate that computing system 1000 ismerely illustrative and is not intended to limit the scope of thetechniques described herein. Computing system 1000 may include anycombination of devices or software that may perform or otherwise providefor the performance of the techniques described herein. For example,computing system 1000 may include or be a combination of acloud-computing system, a data center, a server rack, a server, avirtual server, a desktop computer, a laptop computer, a tabletcomputer, a server device, a client device, a mobile telephone, apersonal digital assistant (PDA), a mobile audio or video player, a gameconsole, a vehicle-mounted computer, or a Global Positioning System(GPS), or the like. Computing system 1000 may also be connected to otherdevices that are not illustrated, or may operate as a stand-alonesystem. In addition, the functionality provided by the illustratedcomponents may in some embodiments be combined in fewer components ordistributed in additional components. Similarly, in some embodiments,the functionality of some of the illustrated components may not beprovided or other additional functionality may be available.

Those skilled in the art will also appreciate that while various itemsare illustrated as being stored in memory or on storage while beingused, these items or portions of them may be transferred between memoryand other storage devices for purposes of memory management and dataintegrity. Alternatively, in other embodiments some or all of thesoftware components may execute in memory on another device andcommunicate with the illustrated computer system via inter-computercommunication. Some or all of the system components or data structuresmay also be stored (e.g., as instructions or structured data) on acomputer-accessible medium or a portable article to be read by anappropriate drive, various examples of which are described above. Insome embodiments, instructions stored on a computer-accessible mediumseparate from computing system 1000 may be transmitted to computingsystem 1000 via transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as a network or a wireless link. Various embodiments may furtherinclude receiving, sending, or storing instructions or data implementedin accordance with the foregoing description upon a computer-accessiblemedium. Accordingly, the present techniques may be practiced with othercomputer system configurations.

In block diagrams, illustrated components are depicted as discretefunctional blocks, but embodiments are not limited to systems in whichthe functionality described herein is organized as illustrated. Thefunctionality provided by each of the components may be provided bysoftware or hardware modules that are differently organized than ispresently depicted, for example such software or hardware may beintermingled, conjoined, replicated, broken up, distributed (e.g.,within a data center or geographically), or otherwise differentlyorganized. The functionality described herein may be provided by one ormore processors of one or more computers executing code stored on atangible, non-transitory, machine-readable medium. In some cases,notwithstanding use of the singular term “medium,” the instructions maybe distributed on different storage devices associated with differentcomputing devices, for instance, with each computing device having adifferent subset of the instructions, an implementation consistent withusage of the singular term “medium” herein. In some cases, third partycontent delivery networks may host some or all of the informationconveyed over networks, in which case, to the extent information (e.g.,content) is said to be supplied or otherwise provided, the informationmay be provided by sending instructions to retrieve that informationfrom a content delivery network.

The reader should appreciate that the present application describesseveral independently useful techniques. Rather than separating thosetechniques into multiple isolated patent applications, applicants havegrouped these techniques into a single document because their relatedsubject matter lends itself to economies in the application process. Butthe distinct advantages and aspects of such techniques should not beconflated. In some cases, embodiments address all of the deficienciesnoted herein, but it should be understood that the techniques areindependently useful, and some embodiments address only a subset of suchproblems or offer other, unmentioned benefits that will be apparent tothose of skill in the art reviewing the present disclosure. Due to costsconstraints, some techniques disclosed herein may not be presentlyclaimed and may be claimed in later filings, such as continuationapplications or by amending the present claims. Similarly, due to spaceconstraints, neither the Abstract nor the Summary of the Inventionsections of the present document should be taken as containing acomprehensive listing of all such techniques or all aspects of suchtechniques.

It should be understood that the description and the drawings are notintended to limit the present techniques to the particular formdisclosed, but to the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present techniques as defined by the appended claims.Further modifications and alternative embodiments of various aspects ofthe techniques will be apparent to those skilled in the art in view ofthis description. Accordingly, this description and the drawings are tobe construed as illustrative only and are for the purpose of teachingthose skilled in the art the general manner of carrying out the presenttechniques. It is to be understood that the forms of the presenttechniques shown and described herein are to be taken as examples ofembodiments. Elements and materials may be substituted for thoseillustrated and described herein, parts and processes may be reversed oromitted, and certain features of the present techniques may be utilizedindependently, all as would be apparent to one skilled in the art afterhaving the benefit of this description of the present techniques.Changes may be made in the elements described herein without departingfrom the spirit and scope of the present techniques as described in thefollowing claims. Headings used herein are for organizational purposesonly and are not meant to be used to limit the scope of the description.

As used throughout this application, the word “may” is used in apermissive sense (i.e., meaning having the potential to), rather thanthe mandatory sense (i.e., meaning must). The words “include,”“including,” and “includes” and the like mean including, but not limitedto. As used throughout this application, the singular forms “a,” “an,”and “the” include plural referents unless the content explicitlyindicates otherwise. Thus, for example, reference to “an element” or “aelement” includes a combination of two or more elements, notwithstandinguse of other terms and phrases for one or more elements, such as “one ormore.” The term “or” is, unless indicated otherwise, non-exclusive,i.e., encompassing both “and” and “or.” Terms describing conditionalrelationships, e.g., “in response to X, Y,” “upon X, Y,”, “if X, Y,”“when X, Y,” and the like, encompass causal relationships in which theantecedent is a necessary causal condition, the antecedent is asufficient causal condition, or the antecedent is a contributory causalcondition of the consequent, e.g., “state X occurs upon condition Yobtaining” is generic to “X occurs solely upon Y” and “X occurs upon Yand Z.” Such conditional relationships are not limited to consequencesthat instantly follow the antecedent obtaining, as some consequences maybe delayed, and in conditional statements, antecedents are connected totheir consequents, e.g., the antecedent is relevant to the likelihood ofthe consequent occurring. Statements in which a plurality of attributesor functions are mapped to a plurality of objects (e.g., one or moreprocessors performing steps A, B, C, and D) encompasses both all suchattributes or functions being mapped to all such objects and subsets ofthe attributes or functions being mapped to subsets of the attributes orfunctions (e.g., both all processors each performing steps A-D, and acase in which processor 1 performs step A, processor 2 performs step Band part of step C, and processor 3 performs part of step C and step D),unless otherwise indicated. Similarly, reference to “a computer system”performing step A and “the computer system” performing step B caninclude the same computing device within the computer system performingboth steps or different computing devices within the computer systemperforming steps A and B. Further, unless otherwise indicated,statements that one value or action is “based on” another condition orvalue encompass both instances in which the condition or value is thesole factor and instances in which the condition or value is one factoramong a plurality of factors. Unless otherwise indicated, statementsthat “each” instance of some collection have some property should not beread to exclude cases where some otherwise identical or similar membersof a larger collection do not have the property, i.e., each does notnecessarily mean each and every. Limitations as to sequence of recitedsteps should not be read into the claims unless explicitly specified,e.g., with explicit language like “after performing X, performing Y,” incontrast to statements that might be improperly argued to imply sequencelimitations, like “performing X on items, performing Y on the X'editems,” used for purposes of making claims more readable rather thanspecifying sequence. Statements referring to “at least Z of A, B, andC,” and the like (e.g., “at least Z of A, B, or C”), refer to at least Zof the listed categories (A, B, and C) and do not require at least Zunits in each category. Unless specifically stated otherwise, asapparent from the discussion, it is appreciated that throughout thisspecification discussions utilizing terms such as “processing,”“computing,” “calculating,” “determining” or the like refer to actionsor processes of a specific apparatus, such as a special purpose computeror a similar special purpose electronic processing/computing device.Features described with reference to geometric constructs, like“parallel,” “perpendicular/orthogonal,” “square,” “cylindrical,” and thelike, should be construed as encompassing items that substantiallyembody the properties of the geometric construct, e.g., reference to“parallel” surfaces encompasses substantially parallel surfaces. Thepermitted range of deviation from Platonic ideals of these geometricconstructs is to be determined with reference to ranges in thespecification, and where such ranges are not stated, with reference toindustry norms in the field of use, and where such ranges are notdefined, with reference to industry norms in the field of manufacturingof the designated feature, and where such ranges are not defined,features substantially embodying a geometric construct should beconstrued to include those features within 15% of the definingattributes of that geometric construct. The terms “first”, “second”,“third,” “given” and so on, if used in the claims, are used todistinguish or otherwise identify, and not to show a sequential ornumerical limitation. As is the case in ordinary usage in the field,data structures and formats described with reference to uses salient toa human need not be presented in a human-intelligible format toconstitute the described data structure or format, e.g., text need notbe rendered or even encoded in Unicode or ASCII to constitute text;images, maps, and data-visualizations need not be displayed or decodedto constitute images, maps, and data-visualizations, respectively;speech, music, and other audio need not be emitted through a speaker ordecoded to constitute speech, music, or other audio, respectively.Computer implemented instructions, commands, and the like are notlimited to executable code and can be implemented in the form of datathat causes functionality to be invoked, e.g., in the form of argumentsof a function or API call.

In this patent, to the extent any U.S. patents, U.S. patentapplications, or other materials (e.g., articles) have been incorporatedby reference, the text of such materials is only incorporated byreference to the extent that no conflict exists between such materialand the statements and drawings set forth herein. In the event of suchconflict, the text of the present document governs, and terms in thisdocument should not be given a narrower reading in virtue of the way inwhich those terms are used in other materials incorporated by reference.

The present techniques will be better understood with reference to thefollowing enumerated embodiments:

A1. A radar assembly, comprising: a transmit antenna assembly withpassive cooling, the transmit antenna assembly, comprising: a firstactive beam-steering circuit configured to control, along a firstspatial dimension, a direction of an electromagnetic beam that scans avolume of an external environment to determine whether objects arelocated within the volume; and a first passive beam-steering circuitconfigured to control, along a second spatial dimension, the directionof the electromagnetic beam, wherein the first passive beam-steeringcircuit comprises: a first set of antenna elements configured totransmit the electromagnetic beam; and a first set of frequency scannedarray cards respectively associated with the first set of antennaelements, wherein each frequency scanned array card of the first set offrequency scanned array cards is configured to cause a phase ofelectromagnetic radiation output by a corresponding antenna element ofthe first set of antenna elements to be shifted by a respective firstamount such that, along the second spatial dimension, theelectromagnetic beam transmitted via the first set of antenna elementsis output in a direction of the volume, wherein the electromagnetic beamis formed based on a combination of the electromagnetic radiation outputby each antenna element of the first set of antenna elements.A2. The radar assembly of embodiment A1, further comprising: a receiveantenna assembly with passive cooling, the receive antenna assemblycomprising: a second passive beam-steering circuit configured tocontrol, along the second spatial dimension, a direction with which toreceive at least some of the electromagnetic radiation of theelectromagnetic beam that reflects off an object located within thevolume, comprising: a second set of antenna elements configured toreceive the reflected electromagnetic radiation; and a second set offrequency scanned array cards respectively associated with the secondset of antenna elements, wherein each frequency scanned array card ofthe second set of frequency scanned array cards is configured to cause aphase of electromagnetic radiation received by a corresponding antennaelement of the second set of antenna elements to be phase-shifted by arespective second amount, the respective second amount being based onthe respective first amount; and a second active beam-steering circuitconfigured to control, along the first spatial dimension, a directionthat the second set of antenna elements scans to detect the reflectedelectromagnetic beam.A3. The radar assembly of embodiment A2, wherein the first activebeam-steering circuit is thermally coupled to a first heatsink such thatheat from the first active beam-steering circuit is conducted to theexternal environment, and the second active beam-steering circuit isthermally coupled to the first heatsink such that heat produced by thesecond active beam-steering circuit is thermally dissipated to theexternal environment via the first heatsink.A4. The radar assembly of any one of embodiments A2-A3, wherein firstpassive beam-steering circuit and the second passive beam-steeringcircuit do not include switches to control a direction of theelectromagnetic beam being transmitted or a direction that the reflectedelectromagnetic beam is received.A5. The radar assembly of any one of embodiments A2-A4, furthercomprising:

means for shielding the transmit antenna assembly and the receiveantenna assembly from at least one of water or particulates.

A6. The radar assembly of any one of embodiments A2-A5, wherein: thetransmit antenna assembly and the receive antenna assembly do notinclude active cooling; and the transmit antenna assembly and thereceive antenna assembly are respectively configured to concurrentlytransmit and receive radar signals.A7. The radar assembly of embodiment A6, wherein the radar assemblyfurther comprises: means for electromagnetically isolating the transmitantenna assembly from the receive antenna assembly.A8. The radar assembly of any one of embodiments A2-A7, wherein thetransmit antenna assembly and the receive antenna assembly operateconcurrently such that the first set of antenna elements transmits theelectromagnetic beam during a same time period that the second set ofantenna elements receives the reflected electromagnetic beam.A9. The radar assembly of any one of embodiments A1-A8, furthercomprises: means for amplifying and steering the electromagnetic beamtransmitted by the first set of antenna elements.A10. The radar assembly of any one of embodiments A1-A9, wherein therespective first amount that an input signal is phase-shifted by eachfrequency scanned array card from the first set of frequency scannedarray cards is determined based on a location, along the second spatialdimension, of the volume in space.A11. The radar assembly of any one of embodiments A1-A10, furthercomprising: a computing system configured to: generate an input signal;and determine the respective first amount of phase-shift to be appliedto the input signal by each antenna element of the first set of antennaelements such that the output electromagnetic beam is directed at thevolume in space.A12. The radar assembly of embodiment A11, wherein the computing systemis further configured to: determine, based on a portion of theelectromagnetic beam that reflects off an object located within thevolume, whether the object is a target to be tracked, wherein a gain ofthe input signal is set based on a predefined range specified for theradar assembly.A13. The radar assembly of any one of embodiments A1-A12, wherein thefirst spatial dimension is orthogonal to the second spatial dimension.A14. The radar assembly of any one of embodiments A1-A13, wherein thefirst active beam-steering circuit comprises a printed circuit boardhaving active electronics disposed thereon, wherein the printed circuitboard is thermally coupled to a heatsink using one or more vias.A15. The radar assembly of any one of embodiments A1-A14, furthercomprising: a receive antenna assembly, comprising: a second passivebeam-steering circuit, comprising a second set of frequency scannedarray cards respectively associated with the first set of antennaelements, wherein each frequency scanned array card of the second set offrequency scanned array cards is configured to cause a phase ofelectromagnetic radiation received by a corresponding antenna element ofthe first set of antenna elements to be phase-shifted by a respectivesecond amount, the respective second amount being based on therespective first amount; and a second active beam-steering circuitconfigured to control, along the first spatial dimension, a directionthat the first set of antenna elements scans to detect reflectedelectromagnetic radiation.A16. The radar assembly of embodiment A15, wherein the second activebeam-steering circuit is thermally coupled to a heatsink.A17. The radar assembly of embodiment A16, further comprising: means foroperating the transmit antenna assembly and the receive antenna assemblyin parallel using the first set of antenna elements.B1. An antenna assembly, comprising: an active beam-steering circuitconfigured to control, along a first spatial dimension, a direction ofan electromagnetic beam that scans a volume of an external environmentto determine whether objects are located within the volume, wherein theactive beam-steering circuit is thermally coupled to a heatsink suchthat heat from the active beam-steering circuit is conducted to theexternal environment; a passive beam-steering circuit configured tocontrol, along a second spatial dimension, the direction of theelectromagnetic beam, wherein the passive beam-steering circuitcomprises: a set of antenna elements configured to transmit theelectromagnetic beam and receive a reflected electromagnetic beamresulting from the electromagnetic beam reflecting off of an object; anda set of frequency scanned array cards respectively associated with theset of antenna elements, wherein each frequency scanned array card ofthe set of frequency scanned array cards is configured to cause an inputsignal to be phase-shifted by a respective amount such that, along thesecond spatial dimension, the electromagnetic beam transmitted via theset of antenna elements is output in a direction of the volume, wherein:the phase-shifted input signal is used by a respective antenna elementof the set of antenna elements to output a respective component of theelectromagnetic beam, and the electromagnetic beam is formed based on acombination of the respective components.B2. The antenna assembly of embodiment B1, wherein the set of frequencyscanned array cards are further configured to detect the reflectedelectromagnetic beam having the respective phase-shift using the set ofantenna elements such that the set of antenna elements transmits theelectromagnetic beam and receives the reflected electromagnetic beam inparallel.C1. A system, comprising: a two-dimensional array antenna divided into aplurality of sub-arrays disposed along a first spatial dimension,wherein each sub-array of the plurality of sub-arrays comprises: aplurality of frequency scannable elements disposed along the firstspatial dimension, and a plurality of phase shifters or transmit/receive(T/R) modules disposed along a second spatial dimension, each phaseshifter or T/R module connected to a plurality of frequency scannableelements disposed along the first spatial dimension, such that phasescanning is provided in the second spatial dimension; and one or moreprocessors coupled to the two-dimensional array antenna, the one or moreprocessors being configured to: generate a recurring radar waveformhaving at least a transmit portion, the transmit portion having multiplesuccessive pulses at different frequencies to cause transmit beams to begenerated by the two-dimensional array antenna at different angles inthe first spatial dimension; control at least one of the plurality ofthe phase shifters or T/R modules along the second spatial dimension tocause the transmit beams to be generated by the two-dimensional arrayantenna at different angles in the second spatial dimension; and processreturn signals received by the plurality of sub-arrays to estimate atarget location in the first spatial dimension and the second spatialdimension, wherein the return signals are associated with the recurringradar waveform.C2. The system of embodiment C1, wherein each sub-array of the pluralityof sub-arrays is coupled to a respective analog-to-digital converter(ADC), and each ADC is coupled to the one or more processors.C3. The system of embodiment C2, wherein the respective ADC coupled toeach sub-array of the plurality of sub-arrays is an only ADC coupled tothat respective sub-array.C4. The system of embodiment C1, wherein: the first spatial dimensioncorresponds to columns of the two-dimensional array antenna; and thesecond spatial dimension corresponds to rows of the two-dimensionalarray antenna.C5. The system of embodiment C4, wherein the first spatial dimension isorthogonal to the second spatial dimension.C6. The system of embodiment C1, wherein the return signals beingprocessed comprises the one or more processors being configured to:perform steps for using interferometric techniques to estimate thetarget location.C7. The system of embodiment C1, wherein the return signals beingprocessed comprises the one or more processors being configured to:perform steps for using maximum likelihood estimation techniques toestimate the target location.C8. The system of embodiment C1, wherein the plurality of frequencyscannable elements comprises a planar card with a series of end-fireantenna elements connected to a common transmission line via couplers,the planar card containing no powered integrated circuitry.C9. The system of embodiment C1, wherein: the two-dimensional arrayantenna is exclusively passively cooled; the plurality of frequencyscannable elements comprises between eight and sixty-four antennaelements; the two-dimensional array antenna is between 5,000 and 40,000cubic centimeters in volume; the different frequencies of the transmitbeams comprise frequencies in the Ku frequency band; and the one or moreprocessors comprise at least one of a field programmable gate array(FPGA), a graphics processing unit (GPU), or a centralized processingunit (CPU).C10. The system of embodiment C1, wherein each sub-array of theplurality of sub-arrays comprises at least two planar cards, whereineach planar card comprises a plurality of antenna elements.C11. The system of embodiment C1, further comprising: a heatsinkthermally coupled to the two-dimensional array antenna, the heatsinkbeing configured to dissipate heat to an external environment.C12. The system of embodiment C11, wherein the heatsink is passivelycooled.C13. The system of embodiment C1, further comprising: means forshielding the two-dimensional array antenna from at least one of wateror particulates.C14. The system of embodiment C1, wherein: the two-dimensional arrayantenna does not include active cooling; and the two-dimensional arrayantenna is configured to concurrently output the transmit beams andreceive the return signals.C15. The system of embodiment C1, wherein the plurality of sub-arrayscomprises: a plurality of receiver antenna sub-arrays configured toreceive the return signals; and a plurality of transmitter antennasub-arrays configured to output the transmit beams.C16. The system of embodiment C15, further comprising: means forelectromagnetically isolating the plurality of receiver antennasub-arrays from the plurality of transmitter antenna sub-arrays.D1. A method, implemented by one or more processors configured toexecute computer program instructions to effectuate the method, themethod comprising: operating a radar comprising a two-dimensional arrayantenna comprising a plurality of sub-arrays disposed along a firstspatial dimension, wherein each sub-array of the plurality of sub-arrayscomprises a plurality of frequency scannable elements disposed along thefirst spatial dimension and a plurality of phase shifters ortransmit/receive (T/R) modules disposed along a second spatialdimension, each phase shifter or T/R module connected to a plurality offrequency scannable elements disposed along the first spatial dimension,such that phase scanning is provided in the second spatial dimension,such that target location in the first spatial dimension and the secondspatial dimension is estimated based on signals received by theplurality of sub-arrays.D2. The method of embodiment D1, further comprising: generating arecurring radar waveform having at least a transmit portion, wherein thetransmit portion has multiple successive pulses at different frequenciesto cause transmit beams to be generated by the two-dimensional arrayantenna at different angles in the first spatial dimension; controllingat least one of the plurality of phase shifters or T/R modules along thesecond spatial dimension to cause the transmit beams to be generated bythe two-dimensional array antenna at different angles in the secondspatial dimension; and processing return signals received by theplurality of sub-arrays to estimate a target location in the firstspatial dimension and the second spatial dimension, wherein the returnsignals are associated with the recurring radar waveform.E1. A system, comprising: a two-dimensional array antenna divided into aplurality of sub-arrays disposed along a first spatial dimension,wherein each sub-array of the plurality of sub-arrays comprises: aplurality of frequency scannable elements disposed along the firstspatial dimension, and a plurality of phase shifters or transmit/receive(T/R) modules disposed along a second spatial dimension, each phaseshifter or T/R module connected to a plurality of frequency scannableelements disposed along the first spatial dimension, such that phasescanning is provided in the second spatial dimension; and one or moreprocessors coupled to the two-dimensional array antenna, the one or moreprocessors being configured to generate output signals to be transmittedto the two-dimensional array antenna and process return signals receivedby the two-dimensional array antenna.E2. The system of embodiment E1, wherein the one or more processors areconfigured to: generate a recurring radar waveform having at least atransmit portion and a receive portion, the transmit portion havingmultiple successive pulses at different frequencies to cause transmitbeams to be generated by the two-dimensional array antenna at differentangles in the first spatial dimension; control at least one of theplurality of phase shifters or T/R modules along the second spatialdimension to cause the transmit beams to be generated by thetwo-dimensional array antenna at different angles in the second spatialdimension; and process return signals received by the plurality ofsub-arrays to estimate a target location in the first spatial dimensionand the second spatial dimension, wherein the return signals areassociated with the recurring radar waveform.

What is claimed is:
 1. A system, comprising: a two-dimensional arrayantenna divided into a plurality of sub-arrays disposed along a firstspatial dimension, wherein each sub-array of the plurality of sub-arrayscomprises: a plurality of frequency scannable elements disposed alongthe first spatial dimension, and a plurality of phase shifters ortransmit/receive (T/R) modules disposed along a second spatialdimension, each phase shifter or T/R module connected to a plurality offrequency scannable elements disposed along the first spatial dimension,such that phase scanning is provided in the second spatial dimension;and one or more processors coupled to the two-dimensional array antenna,the one or more processors being configured to: generate a recurringradar waveform having at least a transmit portion, the transmit portionhaving multiple successive pulses at different frequencies to causetransmit beams to be generated by the two-dimensional array antenna atdifferent angles in the first spatial dimension; control at least one ofthe plurality of the phase shifters or T/R modules along the secondspatial dimension to cause the transmit beams to be generated by thetwo-dimensional array antenna at different angles in the second spatialdimension; and process return signals received by the plurality ofsub-arrays to estimate a target location in the first spatial dimensionand the second spatial dimension, wherein the return signals areassociated with the recurring radar waveform.
 2. The system of claim 1,wherein each sub-array of the plurality of sub-arrays is coupled to arespective analog-to-digital converter (ADC), and each ADC is coupled tothe one or more processors.
 3. The system of claim 2, wherein therespective ADC coupled to each sub-array of the plurality of sub-arraysis an only ADC coupled to that respective sub-array.
 4. The system ofclaim 1, wherein: the first spatial dimension corresponds to columns ofthe two-dimensional array antenna; and the second spatial dimensioncorresponds to rows of the two-dimensional array antenna.
 5. The systemof claim 4, wherein the first spatial dimension is orthogonal to thesecond spatial dimension.
 6. The system of claim 1, wherein the returnsignals being processed comprises the one or more processors beingconfigured to: perform steps for using interferometric techniques toestimate the target location.
 7. The system of claim 1, wherein thereturn signals being processed comprises the one or more processorsbeing configured to: perform steps for using maximum likelihoodestimation techniques to estimate the target location.
 8. The system ofclaim 1, wherein the plurality of frequency scannable elements comprisesa planar card with a series of end-fire antenna elements connected to acommon transmission line via couplers, the planar card containing nopowered integrated circuitry.
 9. The system of claim 1, wherein: thetwo-dimensional array antenna is exclusively passively cooled; theplurality of frequency scannable elements comprises between eight andsixty-four antenna elements; the two-dimensional array antenna isbetween 5,000 and 40,000 cubic centimeters in volume; the differentfrequencies of the transmit beams comprise frequencies in the Kufrequency band; and the one or more processors comprise at least one ofa field programmable gate array (FPGA), a graphics processing unit(GPU), or a centralized processing unit (CPU).
 10. The system of claim1, wherein each sub-array of the plurality of sub-arrays comprises atleast two planar cards, wherein each planar card comprises a pluralityof antenna elements.
 11. The system of claim 1, further comprising: aheatsink thermally coupled to the two-dimensional array antenna, theheatsink being configured to dissipate heat to an external environment.12. The system of claim 11, wherein the heatsink is passively cooled.13. The system of claim 1, further comprising: means for shielding thetwo-dimensional array antenna from at least one of water orparticulates.
 14. The system of claim 1, wherein: the two-dimensionalarray antenna does not include active cooling; and the two-dimensionalarray antenna is configured to concurrently output the transmit beamsand receive the return signals.
 15. The system of claim 1, wherein theplurality of sub-arrays comprises: a plurality of receiver antennasub-arrays configured to receive the return signals; and a plurality oftransmitter antenna sub-arrays configured to output the transmit beams.16. The system of claim 15, further comprising: means forelectromagnetically isolating the plurality of receiver antennasub-arrays from the plurality of transmitter antenna sub-arrays.
 17. Amethod, implemented by one or more processors configured to executecomputer program instructions to effectuate the method, the methodcomprising: operating a radar comprising a two-dimensional array antennacomprising a plurality of sub-arrays disposed along a first spatialdimension, wherein each sub-array of the plurality of sub-arrayscomprises a plurality of frequency scannable elements disposed along thefirst spatial dimension and a plurality of phase shifters ortransmit/receive (T/R) modules disposed along a second spatialdimension, each phase shifter or T/R module connected to a plurality offrequency scannable elements disposed along the first spatial dimension,such that phase scanning is provided in the second spatial dimension,such that target location in the first spatial dimension and the secondspatial dimension is estimated based on signals received by theplurality of sub-arrays.
 18. The method of claim 17, further comprising:generating a recurring radar waveform having at least a transmitportion, wherein the transmit portion has multiple successive pulses atdifferent frequencies to cause transmit beams to be generated by thetwo-dimensional array antenna at different angles in the first spatialdimension; controlling at least one of the plurality of phase shiftersor T/R modules along the second spatial dimension to cause the transmitbeams to be generated by the two-dimensional array antenna at differentangles in the second spatial dimension; and processing return signalsreceived by the plurality of sub-arrays to estimate a target location inthe first spatial dimension and the second spatial dimension, whereinthe return signals are associated with the recurring radar waveform. 19.A system, comprising: a two-dimensional array antenna divided into aplurality of sub-arrays disposed along a first spatial dimension,wherein each sub-array of the plurality of sub-arrays comprises: aplurality of frequency scannable elements disposed along the firstspatial dimension, and a plurality of phase shifters or transmit/receive(T/R) modules disposed along a second spatial dimension, each phaseshifter or T/R module connected to a plurality of frequency scannableelements disposed along the first spatial dimension, such that phasescanning is provided in the second spatial dimension; and one or moreprocessors coupled to the two-dimensional array antenna, the one or moreprocessors being configured to generate output signals to be transmittedto the two-dimensional array antenna and process return signals receivedby the two-dimensional array antenna.
 20. The system of claim 19,wherein the one or more processors are configured to: generate arecurring radar waveform having at least a transmit portion and areceive portion, the transmit portion having multiple successive pulsesat different frequencies to cause transmit beams to be generated by thetwo-dimensional array antenna at different angles in the first spatialdimension; control at least one of the plurality of phase shifters orT/R modules along the second spatial dimension to cause the transmitbeams to be generated by the two-dimensional array antenna at differentangles in the second spatial dimension; and process return signalsreceived by the plurality of sub-arrays to estimate a target location inthe first spatial dimension and the second spatial dimension, whereinthe return signals are associated with the recurring radar waveform.